# EDGAR Filing Document

**Accession Number:** 0000918571
**File Stem:** 0001145549-25-054211
**Filing Date:** 2025-8
**Character Count:** 721923
**Document Hash:** f0c730d1805fdf829a153e6d5e653bcc
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-054211.hdr.sgml**: 20250827

**ACCESSION NUMBER**: 0001145549-25-054211

**CONFORMED SUBMISSION TYPE**: N-CSRS

**PUBLIC DOCUMENT COUNT**: 16

**CONFORMED PERIOD OF REPORT**: 20250630

**FILED AS OF DATE**: 20250827

**DATE AS OF CHANGE**: 20250827

**EFFECTIVENESS DATE**: 20250827

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MFS VARIABLE INSURANCE TRUST
- **CENTRAL INDEX KEY:** 0000918571

**ORGANIZATION NAME:**
- **EIN:** 043226600
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** N-CSRS
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-08326
- **FILM NUMBER:** 251260814

**BUSINESS ADDRESS:**
- **STREET 1:** 111 HUNTINGTON AVENUE
- **STREET 2:** 21ST FLOOR
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02199
- **BUSINESS PHONE:** 18006372929

**MAIL ADDRESS:**
- **STREET 1:** 111 HUNTINGTON AVENUE
- **STREET 2:** 21ST FLOOR
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02199

## Series and Classes Contracts Data

### MFS Total Return Bond Series (Series ID: S000002666)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007302 | Initial Class |  |
| C000007303 | Service Class |  |

### MFS Research Series (Series ID: S000002668)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007306 | Initial Class |  |
| C000007307 | Service Class |  |

### MFS Total Return Series (Series ID: S000002670)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007310 | Initial Class |  |
| C000007311 | Service Class |  |

### MFS Utilities Series (Series ID: S000002671)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007312 | Initial Class |  |
| C000007313 | Service Class |  |

### MFS Value Series (Series ID: S000002672)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007314 | Initial Class |  |
| C000007315 | Service Class |  |

### MFS Growth Series (Series ID: S000002673)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007316 | Initial Class |  |
| C000007317 | Service Class |  |

### MFS Global Equity Series (Series ID: S000002674)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007318 | Initial Class |  |
| C000007319 | Service Class |  |

### MFS Investors Trust Series (Series ID: S000002677)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007324 | Initial Class |  |
| C000007325 | Service Class |  |

### MFS Mid Cap Growth Series (Series ID: S000002678)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007326 | Initial Class |  |
| C000007327 | Service Class |  |

### MFS New Discovery Series (Series ID: S000002680)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000007329 | Initial Class |  |
| C000007330 | Service Class |  |

?xml version='1.0' encoding='ASCII'? 8dde4a21f342d20

#### UNITED STATES

#### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

------

#### FORM N-CSR

------

#### CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES

#### Investment Company Act file number

#### 811-08326

#### MFS VARIABLE INSURANCE TRUST
(Exact name of registrant as specified in charter)

------

111 Huntington Avenue, Boston, Massachusetts 02199

(Address of principal executive offices) (Zip code)

Christopher R. Bohane

Massachusetts Financial Services Company

111 Huntington Avenue

Boston, Massachusetts 02199

(Name and address of agents for service)

#### Registrant's telephone number, including area code:
&nbsp;&nbsp;&nbsp;&nbsp;(617) 954-5000

#### Date of fiscal year end:

#### December 31

#### Date of reporting period:

#### June 30, 2025

#### ITEM 1. REPORTS TO STOCKHOLDERS.
Item 1(a):

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Growth Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Growth Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $37 | 0.72% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 2234002792 | Portfolio Turnover Rate (%): | 19 |
| Total Number of Holdings: | 71 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.6% |
| Money Market Funds | 0.4% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Information Technology | 38.6% |
| Communication Services | 17.3% |
| Financials | 11.2% |
| Consumer Discretionary | 10.5% |
| Industrials | 9.0% |
| Health Care | 6.5% |
| Materials | 2.0% |
| Consumer Staples | 1.8% |
| Energy | 1.0% |
| Utilities | 0.9% |
| Real Estate | 0.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 12.7% |
| NVIDIA Corp. | 9.0% |
| Amazon.com, Inc. | 7.7% |
| Meta Platforms, Inc., "A" | 7.5% |
| Apple, Inc. | 4.4% |
| Alphabet, Inc., "A" | 3.8% |
| Mastercard, Inc., "A" | 3.6% |
| Netflix, Inc. | 3.1% |
| Spotify Technology S.A. | 2.0% |
| Amphenol Corp., "A" | 1.9% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VEGIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Growth Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Growth Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $50 | 0.97% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 2234002792 | Portfolio Turnover Rate (%): | 19 |
| Total Number of Holdings: | 71 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.6% |
| Money Market Funds | 0.4% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Information Technology | 38.6% |
| Communication Services | 17.3% |
| Financials | 11.2% |
| Consumer Discretionary | 10.5% |
| Industrials | 9.0% |
| Health Care | 6.5% |
| Materials | 2.0% |
| Consumer Staples | 1.8% |
| Energy | 1.0% |
| Utilities | 0.9% |
| Real Estate | 0.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 12.7% |
| NVIDIA Corp. | 9.0% |
| Amazon.com, Inc. | 7.7% |
| Meta Platforms, Inc., "A" | 7.5% |
| Apple, Inc. | 4.4% |
| Alphabet, Inc., "A" | 3.8% |
| Mastercard, Inc., "A" | 3.6% |
| Netflix, Inc. | 3.1% |
| Spotify Technology S.A. | 2.0% |
| Amphenol Corp., "A" | 1.9% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VEGSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Total Return Bond Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Total Return Bond Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $27 | 0.53% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 1487531062 | Average Effective Maturity (yrs): | 7.2 |
| Total Number of Holdings: | 746 | Average Effective Duration (yrs): | 6.0 |
| Portfolio Turnover Rate (%): | 29 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Fixed Income | 98.1% |
| Money Market Funds | 1.9% |

---

 **Composition including fixed income credit quality**

---

| | |
|:---|:---|
| AAA | 11.3% |
| AA | 4.7% |
| A | 10.0% |
| BBB | 24.3% |
| BB | 4.2% |
| B | 2.4% |
| U.S. Government | 22.4% |
| Federal Agencies | 18.4% |
| Not Rated | 0.4% |
| Money Market Funds | 1.9% |

---

Ratings are assigned using Moody's, Fitch, and Standard & Poor's and applying a hierarchy: If all 3 agencies rate a security, the middle rating is assigned; if 2 agencies rate a security, the lower rating is assigned. If none of the 3 agencies rate a security, we use DBRS Morningstar. If none of the 4 agencies rate a security, we use Kroll Bond Rating Agency. Ratings are shown in the S&P and Fitch scale (e.g., AAA). All ratings are subject to change.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VFBIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Total Return Bond Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Total Return Bond Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $39 | 0.78% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 1487531062 | Average Effective Maturity (yrs): | 7.2 |
| Total Number of Holdings: | 746 | Average Effective Duration (yrs): | 6.0 |
| Portfolio Turnover Rate (%): | 29 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Fixed Income | 98.1% |
| Money Market Funds | 1.9% |

---

 **Composition including fixed income credit quality**

---

| | |
|:---|:---|
| AAA | 11.3% |
| AA | 4.7% |
| A | 10.0% |
| BBB | 24.3% |
| BB | 4.2% |
| B | 2.4% |
| U.S. Government | 22.4% |
| Federal Agencies | 18.4% |
| Not Rated | 0.4% |
| Money Market Funds | 1.9% |

---

Ratings are assigned using Moody's, Fitch, and Standard & Poor's and applying a hierarchy: If all 3 agencies rate a security, the middle rating is assigned; if 2 agencies rate a security, the lower rating is assigned. If none of the 3 agencies rate a security, we use DBRS Morningstar. If none of the 4 agencies rate a security, we use Kroll Bond Rating Agency. Ratings are shown in the S&P and Fitch scale (e.g., AAA). All ratings are subject to change.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VFBSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Research Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Research Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $39 | 0.76% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 379864219 | Portfolio Turnover Rate (%): | 22 |
| Total Number of Holdings: | 106 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.1% |
| Money Market Funds | 0.9% |

---

 **Global equity sectors**

---

| | |
|:---|:---|
| Technology | 32.5% |
| Financial Services | 13.8% |
| Capital Goods | 12.7% |
| Consumer Cyclicals | 11.2% |
| Communication Services | 10.1% |
| Health Care | 9.9% |
| Energy | 5.4% |
| Consumer Staples | 3.5% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 8.6% |
| NVIDIA Corp. | 5.4% |
| Amazon.com, Inc. | 4.8% |
| Meta Platforms, Inc., "A" | 4.7% |
| Apple, Inc. | 4.1% |
| Mastercard, Inc., "A" | 3.0% |
| JPMorgan Chase & Co. | 2.6% |
| Alphabet, Inc., "A" | 2.5% |
| Broadcom, Inc. | 2.5% |
| Salesforce, Inc. | 1.4% |

---

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VFRIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Research Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Research Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $51 | 1.01% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 379864219 | Portfolio Turnover Rate (%): | 22 |
| Total Number of Holdings: | 106 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.1% |
| Money Market Funds | 0.9% |

---

 **Global equity sectors**

---

| | |
|:---|:---|
| Technology | 32.5% |
| Financial Services | 13.8% |
| Capital Goods | 12.7% |
| Consumer Cyclicals | 11.2% |
| Communication Services | 10.1% |
| Health Care | 9.9% |
| Energy | 5.4% |
| Consumer Staples | 3.5% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 8.6% |
| NVIDIA Corp. | 5.4% |
| Amazon.com, Inc. | 4.8% |
| Meta Platforms, Inc., "A" | 4.7% |
| Apple, Inc. | 4.1% |
| Mastercard, Inc., "A" | 3.0% |
| JPMorgan Chase & Co. | 2.6% |
| Alphabet, Inc., "A" | 2.5% |
| Broadcom, Inc. | 2.5% |
| Salesforce, Inc. | 1.4% |

---

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VFRSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Global Equity Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Global Equity Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $48 | 0.92% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 48017720 | Portfolio Turnover Rate (%):<sub>10</sub> |
| Total Number of Holdings: | 86 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 97.1% |
| Money Market Funds | 2.9% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Visa, Inc., "A" | 3.4% |
| Microsoft Corp. | 3.3% |
| Charles Schwab Corp. | 2.6% |
| Schneider Electric SE | 2.5% |
| Medtronic PLC | 2.4% |
| Willis Towers Watson PLC | 2.3% |
| Alphabet, Inc., "A" | 2.3% |
| Honeywell International, Inc. | 2.1% |
| Becton, Dickinson and Co. | 2.0% |
| Amadeus IT Group S.A. | 1.9% |

---

 **Issuer country weightings**

---

| | |
|:---|:---|
| United States | 52.9% |
| France | 10.7% |
| United Kingdom | 9.3% |
| Switzerland | 7.0% |
| Spain | 4.0% |
| Germany | 3.2% |
| Canada | 2.9% |
| Netherlands | 2.1% |
| Japan | 1.4% |
| Other Countries | 6.5% |

---

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VGEIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Global Equity Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Global Equity Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $60 | 1.17% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 48017720 | Portfolio Turnover Rate (%):<sub>10</sub> |
| Total Number of Holdings: | 86 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 97.1% |
| Money Market Funds | 2.9% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Visa, Inc., "A" | 3.4% |
| Microsoft Corp. | 3.3% |
| Charles Schwab Corp. | 2.6% |
| Schneider Electric SE | 2.5% |
| Medtronic PLC | 2.4% |
| Willis Towers Watson PLC | 2.3% |
| Alphabet, Inc., "A" | 2.3% |
| Honeywell International, Inc. | 2.1% |
| Becton, Dickinson and Co. | 2.0% |
| Amadeus IT Group S.A. | 1.9% |

---

 **Issuer country weightings**

---

| | |
|:---|:---|
| United States | 52.9% |
| France | 10.7% |
| United Kingdom | 9.3% |
| Switzerland | 7.0% |
| Spain | 4.0% |
| Germany | 3.2% |
| Canada | 2.9% |
| Netherlands | 2.1% |
| Japan | 1.4% |
| Other Countries | 6.5% |

---

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VGESC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Investors Trust Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Investors Trust Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $38 | 0.74% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 297293121 | Portfolio Turnover Rate (%):<sub>14</sub> |
| Total Number of Holdings: | 66 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.6% |
| Money Market Funds | 0.4% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Information Technology | 29.2% |
| Financials | 18.1% |
| Industrials | 11.4% |
| Health Care | 11.0% |
| Consumer Discretionary | 8.1% |
| Communication Services | 7.9% |
| Consumer Staples | 5.6% |
| Utilities | 3.1% |
| Energy | 2.6% |
| Real Estate | 1.5% |
| Materials | 1.1% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 9.1% |
| NVIDIA Corp. | 5.8% |
| Amazon.com, Inc. | 5.3% |
| Meta Platforms, Inc., "A" | 4.1% |
| Alphabet, Inc., "A" | 3.8% |
| Apple, Inc. | 3.5% |
| JPMorgan Chase & Co. | 2.8% |
| Visa, Inc., "A" | 2.2% |
| Salesforce, Inc. | 2.0% |
| Mastercard, Inc., "A" | 2.0% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VGIIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Investors Trust Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Investors Trust Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $50 | 0.99% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 297293121 | Portfolio Turnover Rate (%):<sub>14</sub> |
| Total Number of Holdings: | 66 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.6% |
| Money Market Funds | 0.4% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Information Technology | 29.2% |
| Financials | 18.1% |
| Industrials | 11.4% |
| Health Care | 11.0% |
| Consumer Discretionary | 8.1% |
| Communication Services | 7.9% |
| Consumer Staples | 5.6% |
| Utilities | 3.1% |
| Energy | 2.6% |
| Real Estate | 1.5% |
| Materials | 1.1% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Microsoft Corp. | 9.1% |
| NVIDIA Corp. | 5.8% |
| Amazon.com, Inc. | 5.3% |
| Meta Platforms, Inc., "A" | 4.1% |
| Alphabet, Inc., "A" | 3.8% |
| Apple, Inc. | 3.5% |
| JPMorgan Chase & Co. | 2.8% |
| Visa, Inc., "A" | 2.2% |
| Salesforce, Inc. | 2.0% |
| Mastercard, Inc., "A" | 2.0% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VGISC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Value Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Value Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $35 | 0.69% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 2567046565 | Portfolio Turnover Rate (%):<sub>6</sub> |
| Total Number of Holdings: | 71 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.0% |
| Money Market Funds | 1.0% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Financials | 31.3% |
| Industrials | 17.2% |
| Health Care | 14.4% |
| Utilities | 9.1% |
| Information Technology | 8.2% |
| Consumer Staples | 6.3% |
| Energy | 5.7% |
| Consumer Discretionary | 3.1% |
| Real Estate | 1.9% |
| Materials | 1.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| JPMorgan Chase & Co. | 4.7% |
| Progressive Corp. | 4.1% |
| Cigna Group | 3.3% |
| McKesson Corp. | 3.1% |
| RTX Corp. | 2.5% |
| Boeing Co. | 2.4% |
| American Express Co. | 2.4% |
| Marsh & McLennan Cos., Inc. | 2.3% |
| Morgan Stanley | 2.1% |
| Duke Energy Corp. | 2.0% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VLUIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Value Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Value Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $48 | 0.94% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 2567046565 | Portfolio Turnover Rate (%):<sub>6</sub> |
| Total Number of Holdings: | 71 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.0% |
| Money Market Funds | 1.0% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Financials | 31.3% |
| Industrials | 17.2% |
| Health Care | 14.4% |
| Utilities | 9.1% |
| Information Technology | 8.2% |
| Consumer Staples | 6.3% |
| Energy | 5.7% |
| Consumer Discretionary | 3.1% |
| Real Estate | 1.9% |
| Materials | 1.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| JPMorgan Chase & Co. | 4.7% |
| Progressive Corp. | 4.1% |
| Cigna Group | 3.3% |
| McKesson Corp. | 3.1% |
| RTX Corp. | 2.5% |
| Boeing Co. | 2.4% |
| American Express Co. | 2.4% |
| Marsh & McLennan Cos., Inc. | 2.3% |
| Morgan Stanley | 2.1% |
| Duke Energy Corp. | 2.0% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VLUSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Mid Cap Growth Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Mid Cap Growth Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $41 | 0.80% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 370118058 | Portfolio Turnover Rate (%): | 28 |
| Total Number of Holdings: | 99 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.5% |
| Money Market Funds | 0.5% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Industrials | 20.3% |
| Information Technology | 18.5% |
| Financials | 13.4% |
| Communication Services | 12.2% |
| Consumer Discretionary | 12.0% |
| Health Care | 11.0% |
| Energy | 4.1% |
| Real Estate | 2.6% |
| Utilities | 2.2% |
| Consumer Staples | 1.8% |
| Materials | 1.4% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Howmet Aerospace, Inc. | 4.7% |
| Spotify Technology S.A. | 3.3% |
| Take-Two Interactive Software, Inc. | 3.2% |
| Guidewire Software, Inc. | 3.1% |
| Axon Enterprise, Inc. | 2.6% |
| Vistra Corp. | 2.2% |
| Verisk Analytics, Inc., "A" | 2.2% |
| LPL Financial Holdings, Inc. | 2.1% |
| Tyler Technologies, Inc. | 2.1% |
| Roblox Corp., "A" | 2.1% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VMGIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Mid Cap Growth Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Mid Cap Growth Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $54 | 1.05% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 370118058 | Portfolio Turnover Rate (%): | 28 |
| Total Number of Holdings: | 99 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.5% |
| Money Market Funds | 0.5% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Industrials | 20.3% |
| Information Technology | 18.5% |
| Financials | 13.4% |
| Communication Services | 12.2% |
| Consumer Discretionary | 12.0% |
| Health Care | 11.0% |
| Energy | 4.1% |
| Real Estate | 2.6% |
| Utilities | 2.2% |
| Consumer Staples | 1.8% |
| Materials | 1.4% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Howmet Aerospace, Inc. | 4.7% |
| Spotify Technology S.A. | 3.3% |
| Take-Two Interactive Software, Inc. | 3.2% |
| Guidewire Software, Inc. | 3.1% |
| Axon Enterprise, Inc. | 2.6% |
| Vistra Corp. | 2.2% |
| Verisk Analytics, Inc., "A" | 2.2% |
| LPL Financial Holdings, Inc. | 2.1% |
| Tyler Technologies, Inc. | 2.1% |
| Roblox Corp., "A" | 2.1% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VMGSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> New Discovery Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS New Discovery Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $44 | 0.87% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 716592844 | Portfolio Turnover Rate (%): | 42 |
| Total Number of Holdings: | 115 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 94.1% |
| Money Market Funds | 5.9% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Health Care | 25.2% |
| Industrials | 20.4% |
| Information Technology | 18.5% |
| Consumer Discretionary | 10.7% |
| Financials | 6.4% |
| Consumer Staples | 3.8% |
| Energy | 3.3% |
| Real Estate | 3.0% |
| Materials | 2.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Flowserve Corp. | 2.1% |
| nVent Electric PLC | 2.1% |
| Genius Sports Ltd. | 1.8% |
| Crane Co. | 1.7% |
| StepStone Group, Inc. | 1.7% |
| U.S. Foods Holding Corp. | 1.6% |
| Globus Medical, Inc. | 1.6% |
| Knife River Corp. | 1.5% |
| Advanced Energy Industries, Inc. | 1.5% |
| QIAGEN N.V. | 1.5% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VNDIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> New Discovery Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS New Discovery Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $57 | 1.12% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 716592844 | Portfolio Turnover Rate (%): | 42 |
| Total Number of Holdings: | 115 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 94.1% |
| Money Market Funds | 5.9% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Health Care | 25.2% |
| Industrials | 20.4% |
| Information Technology | 18.5% |
| Consumer Discretionary | 10.7% |
| Financials | 6.4% |
| Consumer Staples | 3.8% |
| Energy | 3.3% |
| Real Estate | 3.0% |
| Materials | 2.8% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| Flowserve Corp. | 2.1% |
| nVent Electric PLC | 2.1% |
| Genius Sports Ltd. | 1.8% |
| Crane Co. | 1.7% |
| StepStone Group, Inc. | 1.7% |
| U.S. Foods Holding Corp. | 1.6% |
| Globus Medical, Inc. | 1.6% |
| Knife River Corp. | 1.5% |
| Advanced Energy Industries, Inc. | 1.5% |
| QIAGEN N.V. | 1.5% |

---

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VNDSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Total Return Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Total Return Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $31 | 0.61% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 2080546997 | Portfolio Turnover Rate (%): | 21 |
| Total Number of Holdings: | 910 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 61.0% |
| Fixed Income | 37.7% |
| Money Market Funds | 1.3% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Financials | 17.3% |
| Health Care | 10.4% |
| Industrials | 7.9% |
| Consumer Staples | 5.0% |
| Information Technology | 4.7% |
| Energy | 3.9% |
| Communication Services | 3.7% |
| Utilities | 3.1% |
| Consumer Discretionary | 2.6% |
| Materials | 2.4% |

---

 **Composition including fixed income credit quality**

---

| | |
|:---|:---|
| AAA | 4.8% |
| AA | 1.8% |
| A | 5.0% |
| BBB | 7.3% |
| CCC | 0.0% |
| U.S. Government | 9.0% |
| Federal Agencies | 9.8% |
| Not Rated | 0.0% |
| Non-Fixed Income | 61.0% |
| Money Market Funds | 1.3% |

---

Ratings are assigned using Moody's, Fitch, and Standard & Poor's and applying a hierarchy: If all 3 agencies rate a security, the middle rating is assigned; if 2 agencies rate a security, the lower rating is assigned. If none of the 3 agencies rate a security, we use DBRS Morningstar. If none of the 4 agencies rate a security, we use Kroll Bond Rating Agency. Ratings are shown in the S&P and Fitch scale (e.g., AAA). All ratings are subject to change.

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VTRIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Total Return Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Total Return Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $44 | 0.86% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | | |
|:---|:---|:---|:---|
| Net Assets ($): | 2080546997 | Portfolio Turnover Rate (%): | 21 |
| Total Number of Holdings: | 910 |  |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 61.0% |
| Fixed Income | 37.7% |
| Money Market Funds | 1.3% |

---

 **Equity sectors**

---

| | |
|:---|:---|
| Financials | 17.3% |
| Health Care | 10.4% |
| Industrials | 7.9% |
| Consumer Staples | 5.0% |
| Information Technology | 4.7% |
| Energy | 3.9% |
| Communication Services | 3.7% |
| Utilities | 3.1% |
| Consumer Discretionary | 2.6% |
| Materials | 2.4% |

---

 **Composition including fixed income credit quality**

---

| | |
|:---|:---|
| AAA | 4.8% |
| AA | 1.8% |
| A | 5.0% |
| BBB | 7.3% |
| CCC | 0.0% |
| U.S. Government | 9.0% |
| Federal Agencies | 9.8% |
| Not Rated | 0.0% |
| Non-Fixed Income | 61.0% |
| Money Market Funds | 1.3% |

---

Ratings are assigned using Moody's, Fitch, and Standard & Poor's and applying a hierarchy: If all 3 agencies rate a security, the middle rating is assigned; if 2 agencies rate a security, the lower rating is assigned. If none of the 3 agencies rate a security, we use DBRS Morningstar. If none of the 4 agencies rate a security, we use Kroll Bond Rating Agency. Ratings are shown in the S&P and Fitch scale (e.g., AAA). All ratings are subject to change.

MFS uses the Global Industry Classification Standard (GICS<sup>®</sup>) for sector/industry reporting. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VTRSC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Utilities Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Initial Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Utilities Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Initial Class | $40 | 0.78% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 1122419775 | Portfolio Turnover Rate (%):<sub>8</sub> |
| Total Number of Holdings: | 39 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.9% |
| Money Market Funds | 0.1% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| NextEra Energy, Inc. | 10.7% |
| Constellation Energy | 8.1% |
| PG&E Corp. | 5.3% |
| Vistra Corp. | 5.1% |
| Xcel Energy, Inc. | 5.0% |
| DTE Energy Co. | 4.6% |
| Sempra Energy | 4.4% |
| Southern Co. | 4.0% |
| Dominion Energy, Inc. | 3.8% |
| American Electric Power Co., Inc. | 3.8% |

---

 **Top five industries**

---

| | |
|:---|:---|
| Utilities - Electric Power | 88.6% |
| Telecom - Infrastructure | 4.0% |
| Natural Gas - Distribution | 2.2% |
| Energy - Renewables | 2.0% |
| Utilities - Water | 1.9% |

---

For purposes of these classifications, MFS uses its own internal sector/industry classification methodology, which may deviate from classification methodologies used by other industry participants (e.g., the Global Industry Classification Standard).

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VUFIC-SEM

![MFSLOGO_RED.EPS](images_1134.jpg)

## MFS<sup>®</sup> Utilities Series

#### MFS<sup>®</sup> Variable Insurance Trust
![TSR_Ribbon_red](images_1139.jpg)

Service Class

Semiannual Shareholder Report

This semiannual shareholder report contains important information about MFS Utilities Series for the period of January 1, 2025 to June 30, 2025. You can find additional information about the fund at insurancefunds.mfs.com. You can also request this information by contacting us at 1-800-225-2606 or by sending an e-mail request to orderliterature@mfs.com.

FUND EXPENSES

What were the fund costs for the last six months?

---

| | | |
|:---|:---|:---|
| *(based on a hypothetical $10,000 investment)* |  |  |
| Class Name | Costs of a $10,000 investment | Costs paid as a percentage of a $10,000 investment (annualized) |
| Service Class | $53 | 1.03% |

---

FUND STATISTICS AS OF 6/30/25

---

| | | |
|:---|:---|:---|
| Net Assets ($): | 1122419775 | Portfolio Turnover Rate (%):<sub>8</sub> |
| Total Number of Holdings: | 39 |  |

---

Where the fund holds derivatives, they are not included in the total number of portfolio holdings.

PORTFOLIO COMPOSITION (BASED ON TOTAL INVESTMENTS AS OF 6/30/25)

 **Portfolio structure**

---

| | |
|:---|:---|
| Equities | 99.9% |
| Money Market Funds | 0.1% |

---

 **Top ten holdings**

---

| | |
|:---|:---|
| NextEra Energy, Inc. | 10.7% |
| Constellation Energy | 8.1% |
| PG&E Corp. | 5.3% |
| Vistra Corp. | 5.1% |
| Xcel Energy, Inc. | 5.0% |
| DTE Energy Co. | 4.6% |
| Sempra Energy | 4.4% |
| Southern Co. | 4.0% |
| Dominion Energy, Inc. | 3.8% |
| American Electric Power Co., Inc. | 3.8% |

---

 **Top five industries**

---

| | |
|:---|:---|
| Utilities - Electric Power | 88.6% |
| Telecom - Infrastructure | 4.0% |
| Natural Gas - Distribution | 2.2% |
| Energy - Renewables | 2.0% |
| Utilities - Water | 1.9% |

---

For purposes of these classifications, MFS uses its own internal sector/industry classification methodology, which may deviate from classification methodologies used by other industry participants (e.g., the Global Industry Classification Standard).

#### ADDITIONAL INFORMATION
You can find the fund's summary prospectus, prospectus, most recent annual and semiannual reports, financial information, portfolio holdings, and statement of additional information online at insurancefunds.mfs.com. Proxy voting information is available without charge by calling 1-800-225-2606, by visiting mfs.com/proxyvoting, or by visiting the SEC's website at http://www.sec.gov.

VUFSC-SEM

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Item 1(b):
Not applicable.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 2. CODE OF ETHICS.
During the period covered by this report, the Registrant has not amended any provision in its Code of Ethics (the "Code") that relates to an element of the Code's definition enumerated in paragraph (b) of Item 2 of this Form N-CSR. During the period covered by this report, the Registrant did not grant a waiver, including an implicit waiver, from any provision of the Code.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.
Not applicable for semi-annual reports.

------

#### ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.
Not applicable for semi-annual reports.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.
Not applicable to the Registrant.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 6. INVESTMENTS
A schedule of investments for each series covered by this Form N-CSR is included in the financial statements of such series under Item 7 of this Form N-CSR.

------

MFS Mid Cap Growth Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Mid Cap Growth Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 99.9% | Common Stocks – 99.9% | Common Stocks – 99.9% |
| Aerospace & Defense – 9.7% | Aerospace & Defense – 9.7% |  |
| Axon Enterprise, Inc. (a) | 11650 | &nbsp;&nbsp; $9645501 |
| BWX Technologies, Inc. | 16482 | &nbsp;&nbsp; 2374397 |
| Curtiss-Wright Corp. | 4462 | &nbsp;&nbsp; 2179910 |
| Hexcel Corp. | 24372 | &nbsp;&nbsp; 1376774 |
| Howmet Aerospace, Inc. | 94406 | &nbsp;&nbsp; 17571789 |
| Melrose Industries PLC | 149885 | &nbsp;&nbsp; 1092066 |
| Mirion Technologies, Inc. (a) | 27428 | &nbsp;&nbsp; 590525 |
| TransDigm Group, Inc. | 619 | &nbsp;&nbsp; 941276 |
|  |  | &nbsp;&nbsp; $35772238 |
| Apparel Manufacturers – 0.1% | Apparel Manufacturers – 0.1% |  |
| VF Corp. | 27829 | &nbsp;&nbsp; $326991 |
| Automotive – 1.5% | Automotive – 1.5% |  |
| ACV Auctions, Inc. (a) | 125048 | &nbsp;&nbsp; $2028278 |
| Copart, Inc. (a) | 69340 | &nbsp;&nbsp; 3402514 |
|  |  | &nbsp;&nbsp; $5430792 |
| Biotechnology – 0.6% | Biotechnology – 0.6% |  |
| Exact Sciences Corp. (a) | 43149 | &nbsp;&nbsp; $2292938 |
| Broadcasting – 5.0% | Broadcasting – 5.0% |  |
| Spotify Technology S.A. (a) | 16078 | &nbsp;&nbsp; $12337292 |
| TKO Group Holdings, Inc. | 34005 | &nbsp;&nbsp; 6187210 |
|  |  | &nbsp;&nbsp; $18524502 |
| Brokerage & Asset Managers – 7.8% | Brokerage & Asset Managers – 7.8% |  |
| Ares Management Co. | 34341 | &nbsp;&nbsp; $5947861 |
| Carlyle Group, Inc. | 76677 | &nbsp;&nbsp; 3941198 |
| LPL Financial Holdings, Inc. | 21175 | &nbsp;&nbsp; 7939990 |
| NASDAQ, Inc. | 58395 | &nbsp;&nbsp; 5221681 |
| TPG, Inc. | 48656 | &nbsp;&nbsp; 2552007 |
| Tradeweb Markets, Inc.  | 23076 | &nbsp;&nbsp; 3378326 |
|  |  | &nbsp;&nbsp; $28981063 |
| Business Services – 6.9% | Business Services – 6.9% |  |
| CoStar Group, Inc. (a) | 55706 | &nbsp;&nbsp; $4478762 |
| Morningstar, Inc. | 10943 | &nbsp;&nbsp; 3435336 |
| MSCI, Inc. | 6054 | &nbsp;&nbsp; 3491584 |
| TransUnion | 67627 | &nbsp;&nbsp; 5951176 |
| Verisk Analytics, Inc., "A" | 26021 | &nbsp;&nbsp; 8105542 |
|  |  | &nbsp;&nbsp; $25462400 |
| Computer Software – 16.5% | Computer Software – 16.5% |  |
| Cadence Design Systems, Inc. (a) | 15127 | &nbsp;&nbsp; $4661385 |
| Cloudflare, Inc., "A" (a) | 11766 | &nbsp;&nbsp; 2304136 |
| Constellation Software, Inc. | 2010 | &nbsp;&nbsp; 7370172 |
| Datadog, Inc., "A" (a) | 36612 | &nbsp;&nbsp; 4918090 |
| Elastic N.V. (a) | 16542 | &nbsp;&nbsp; 1394987 |
| Guidewire Software, Inc. (a) | 48187 | &nbsp;&nbsp; 11345629 |

---

VMGFS-SEM

------

MFS Mid Cap Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Computer Software – continued | Computer Software – continued |  |
| HubSpot, Inc. (a) | 7598 | &nbsp;&nbsp; $4229275 |
| Manhattan Associates, Inc. (a) | 6486 | &nbsp;&nbsp; 1280791 |
| Okta, Inc. (a) | 44257 | &nbsp;&nbsp; 4424372 |
| Pegasystems, Inc. | 28102 | &nbsp;&nbsp; 1521161 |
| PTC, Inc. (a) | 9164 | &nbsp;&nbsp; 1579324 |
| Robinhood Markets, Inc. (a) | 57789 | &nbsp;&nbsp; 5410784 |
| ServiceNow, Inc. (a) | 2215 | &nbsp;&nbsp; 2277197 |
| ServiceTitan, Inc., "A" (a) | 6595 | &nbsp;&nbsp; 706852 |
| Tyler Technologies, Inc. (a) | 13154 | &nbsp;&nbsp; 7798217 |
|  |  | &nbsp;&nbsp; $61222372 |
| Computer Software - Systems – 1.2% | Computer Software - Systems – 1.2% |  |
| Block, Inc., "A" (a) | 29604 | &nbsp;&nbsp; $2011000 |
| CDW Corp. | 2409 | &nbsp;&nbsp; 430223 |
| Q2 Holdings, Inc. (a) | 22788 | &nbsp;&nbsp; 2132729 |
|  |  | &nbsp;&nbsp; $4573952 |
| Construction – 1.4% | Construction – 1.4% |  |
| Vulcan Materials Co. | 19768 | &nbsp;&nbsp; $5155890 |
| Consumer Products – 0.7% | Consumer Products – 0.7% |  |
| Church & Dwight Co., Inc. | 6368 | &nbsp;&nbsp; $612029 |
| ODDITY Tech Ltd. (a) | 25907 | &nbsp;&nbsp; 1955201 |
|  |  | &nbsp;&nbsp; $2567230 |
| Consumer Services – 1.5% | Consumer Services – 1.5% |  |
| Bright Horizons Family Solutions, Inc. (a) | 40279 | &nbsp;&nbsp; $4978082 |
| Expedia Group, Inc. | 2755 | &nbsp;&nbsp; 464713 |
|  |  | &nbsp;&nbsp; $5442795 |
| Electrical Equipment – 1.5% | Electrical Equipment – 1.5% |  |
| AMETEK, Inc. | 16316 | &nbsp;&nbsp; $2952543 |
| Hubbell, Inc. | 2149 | &nbsp;&nbsp; 877673 |
| Vertiv Holdings Co. | 12653 | &nbsp;&nbsp; 1624772 |
|  |  | &nbsp;&nbsp; $5454988 |
| Electronics – 2.2% | Electronics – 2.2% |  |
| ASM International N.V. | 1822 | &nbsp;&nbsp; $1166259 |
| Astera Labs, Inc. (a) | 18200 | &nbsp;&nbsp; 1645644 |
| Monolithic Power Systems, Inc. | 7296 | &nbsp;&nbsp; 5336149 |
|  |  | &nbsp;&nbsp; $8148052 |
| Energy - Independent – 1.5% | Energy - Independent – 1.5% |  |
| Expand Energy Corp. | 47981 | &nbsp;&nbsp; $5610898 |
| Engineering - Construction – 1.1% | Engineering - Construction – 1.1% |  |
| Quanta Services, Inc. | 10999 | &nbsp;&nbsp; $4158502 |
| Entertainment – 2.0% | Entertainment – 2.0% |  |
| Live Nation Entertainment, Inc. (a) | 48947 | &nbsp;&nbsp; $7404702 |
| Gaming & Lodging – 3.3% | Gaming & Lodging – 3.3% |  |
| DraftKings, Inc. (a) | 120901 | &nbsp;&nbsp; $5185444 |
| Hyatt Hotels Corp. | 18197 | &nbsp;&nbsp; 2541211 |
| Royal Caribbean Cruises Ltd. | 4725 | &nbsp;&nbsp; 1479586 |

---

------

MFS Mid Cap Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Gaming & Lodging – continued | Gaming & Lodging – continued |  |
| Sportradar Group AG (a) | 63107 | &nbsp;&nbsp; $1772045 |
| Viking Holdings Ltd. (a) | 25832 | &nbsp;&nbsp; 1376587 |
|  |  | &nbsp;&nbsp; $12354873 |
| General Merchandise – 0.4% | General Merchandise – 0.4% |  |
| Dollar General Corp. | 13708 | &nbsp;&nbsp; $1567921 |
| Insurance – 1.7% | Insurance – 1.7% |  |
| Arthur J. Gallagher & Co. | 19899 | &nbsp;&nbsp; $6370068 |
| Internet – 0.5% | Internet – 0.5% |  |
| Gartner, Inc. (a) | 4412 | &nbsp;&nbsp; $1783419 |
| Leisure & Toys – 5.3% | Leisure & Toys – 5.3% |  |
| Roblox Corp., "A" (a) | 73039 | &nbsp;&nbsp; $7683703 |
| Take-Two Interactive Software, Inc. (a) | 48717 | &nbsp;&nbsp; 11830923 |
|  |  | &nbsp;&nbsp; $19514626 |
| Machinery & Tools – 1.8% | Machinery & Tools – 1.8% |  |
| Wabtec Corp. | 31345 | &nbsp;&nbsp; $6562076 |
| Medical & Health Technology & Services – 1.5% | Medical & Health Technology & Services – 1.5% |  |
| Tempus AI, Inc. (a)(l) | 5434 | &nbsp;&nbsp; $345276 |
| Veeva Systems, Inc. (a) | 18274 | &nbsp;&nbsp; 5262547 |
|  |  | &nbsp;&nbsp; $5607823 |
| Medical Equipment – 7.5% | Medical Equipment – 7.5% |  |
| Agilent Technologies, Inc. | 24137 | &nbsp;&nbsp; $2848407 |
| Bio-Techne Corp. | 4033 | &nbsp;&nbsp; 207498 |
| Caris Life Sciences, Inc. (a) | 11978 | &nbsp;&nbsp; 320052 |
| DexCom, Inc. (a) | 65878 | &nbsp;&nbsp; 5750490 |
| Masimo Corp. (a) | 40985 | &nbsp;&nbsp; 6894497 |
| Natera, Inc. (a) | 34244 | &nbsp;&nbsp; 5785181 |
| STERIS PLC | 16258 | &nbsp;&nbsp; 3905497 |
| Waters Corp. (a) | 5567 | &nbsp;&nbsp; 1943106 |
|  |  | &nbsp;&nbsp; $27654728 |
| Metals & Mining – 0.7% | Metals & Mining – 0.7% |  |
| Cameco Corp. | 34291 | &nbsp;&nbsp; $2545421 |
| Natural Gas - Pipeline – 1.9% | Natural Gas - Pipeline – 1.9% |  |
| Cheniere Energy, Inc. | 28240 | &nbsp;&nbsp; $6877005 |
| Pharmaceuticals – 1.4% | Pharmaceuticals – 1.4% |  |
| Ascendis Pharma, ADR (a) | 30890 | &nbsp;&nbsp; $5331614 |
| Pollution Control – 1.0% | Pollution Control – 1.0% |  |
| GFL Environmental, Inc. | 72500 | &nbsp;&nbsp; $3658350 |
| Printing & Publishing – 0.2% | Printing & Publishing – 0.2% |  |
| Wolters Kluwer N.V. | 5479 | &nbsp;&nbsp; $916144 |
| Real Estate – 1.4% | Real Estate – 1.4% |  |
| CBRE Group, Inc., "A" (a) | 35994 | &nbsp;&nbsp; $5043479 |

---

------

MFS Mid Cap Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Restaurants – 1.9% | Restaurants – 1.9% |  |
| Aramark | 65142 | &nbsp;&nbsp; $2727496 |
| Chipotle Mexican Grill, Inc., "A" (a) | 18761 | &nbsp;&nbsp; 1053430 |
| Wingstop, Inc. | 9293 | &nbsp;&nbsp; 3129325 |
|  |  | &nbsp;&nbsp; $6910251 |
| Specialty Stores – 6.0% | Specialty Stores – 6.0% |  |
| BJ's Wholesale Club Holdings, Inc. (a) | 23823 | &nbsp;&nbsp; $2568834 |
| Burlington Stores, Inc. (a) | 14486 | &nbsp;&nbsp; 3370023 |
| Carvana Co. (a) | 9830 | &nbsp;&nbsp; 3312317 |
| Chewy, Inc., "A" (a) | 27480 | &nbsp;&nbsp; 1171197 |
| Coupang, Inc. (a) | 185900 | &nbsp;&nbsp; 5569564 |
| Floor & Decor Holdings, Inc., "A" (a) | 10778 | &nbsp;&nbsp; 818697 |
| O'Reilly Automotive, Inc. (a) | 50724 | &nbsp;&nbsp; 4571754 |
| Tractor Supply Co. | 16322 | &nbsp;&nbsp; 861312 |
|  |  | &nbsp;&nbsp; $22243698 |
| Utilities - Electric Power – 2.2% | Utilities - Electric Power – 2.2% |  |
| Vistra Corp. | 42813 | &nbsp;&nbsp; $8297588 |
| **Total Common Stocks (Identified Cost, $219,757,826)** |  | &nbsp;&nbsp; **$369769389** |

---

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Strike** <br>**Price**<br>| &nbsp;&nbsp; **First** <br>**Exercise**<br>|  |  |
| Warrants – 0.0% |  |  |  |  |
| Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% |
| Constellation Software, Inc. (CAD 100 principal amount of Series 2 Debentures for 1 warrant, Expiration 3/31/40) (a) <br> (Identified Cost, $0)<br>| CAD 11.5 | N/A | 2984 | &nbsp;&nbsp; $0 |

---

---

| | | |
|:---|:---|:---|
| Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% |
| Money Market Funds – 0.4% | Money Market Funds – 0.4% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $1,461,780) | 1461779 | &nbsp;&nbsp; $1461925 |
| Collateral for Securities Loaned – 0.1% | Collateral for Securities Loaned – 0.1% | Collateral for Securities Loaned – 0.1% |
| JPMorgan U.S. Government Money Market Fund - Class IM Shares, 4.26% (j) (Identified Cost, $326,400) | 326400 | &nbsp;&nbsp; $326400 |
| Other Assets, Less Liabilities – (0.4)% |  | &nbsp;&nbsp; (1439656) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$370118058** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $1,461,925 and $370,095,789, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(j) The rate quoted is the annualized seven-day yield of the fund at period end.

&nbsp;&nbsp;&nbsp;&nbsp;(l) A portion of this security is on loan. See Note 2 for additional information.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

------

MFS Mid Cap Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| ADR | American Depositary Receipt |
| Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: | Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: |
| CAD | Canadian Dollar |

---

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value, including $304,992 of securities on loan (identified cost, $220,084,226) | &nbsp;&nbsp; $370095789 |
| Investments in affiliated issuers, at value (identified cost, $1,461,780) | &nbsp;&nbsp; 1461925 |
| Foreign currency, at value (identified cost, $21) | &nbsp;&nbsp; 21 |
| Receivables for |  |
| Fund shares sold | &nbsp;&nbsp; 138047 |
| Interest and dividends | &nbsp;&nbsp; 14599 |
| Other assets | &nbsp;&nbsp; 518 |
| Total assets | &nbsp;&nbsp; $371710899 |
| **Liabilities** |  |
| Payable to custodian | &nbsp;&nbsp; $35 |
| Payables for |  |
| Fund shares reacquired | &nbsp;&nbsp; 1169968 |
| Collateral for securities loaned, at value | &nbsp;&nbsp; 326400 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 29557 |
| Administrative services fee | &nbsp;&nbsp; 630 |
| Shareholder servicing costs | &nbsp;&nbsp; 379 |
| Distribution and/or service fees | &nbsp;&nbsp; 3714 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 1499 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 60659 |
| Total liabilities | &nbsp;&nbsp; $1592841 |
| Net assets | &nbsp;&nbsp; $370118058 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $142295375 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 227822683 |
| Net assets | &nbsp;&nbsp; $370118058 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 39415181 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $233210187 | &nbsp;&nbsp;&nbsp; 23344293 | &nbsp;&nbsp;&nbsp; $9.99 |
| Service Class | &nbsp;&nbsp;&nbsp; 136907871 | &nbsp;&nbsp;&nbsp; 16070888 | &nbsp;&nbsp;&nbsp;&nbsp;8.52 |

---

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $732490 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 105349 |
| Other | &nbsp;&nbsp; 8269 |
| Income on securities loaned | &nbsp;&nbsp; 6821 |
| Foreign taxes withheld | &nbsp;&nbsp; (8046)<br>|
| Total investment income | &nbsp;&nbsp; $844883 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $1302178 |
| Distribution and/or service fees | &nbsp;&nbsp; 160791 |
| Shareholder servicing costs | &nbsp;&nbsp; 7482 |
| Administrative services fee | &nbsp;&nbsp; 28235 |
| Independent Trustees' compensation | &nbsp;&nbsp; 4623 |
| Custodian fee | &nbsp;&nbsp; 12357 |
| Shareholder communications | &nbsp;&nbsp; 5958 |
| Audit and tax fees | &nbsp;&nbsp; 35751 |
| Legal fees | &nbsp;&nbsp; 916 |
| Miscellaneous | &nbsp;&nbsp; 15290 |
| Total expenses | &nbsp;&nbsp; $1573581 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (24142)<br>|
| Net expenses | &nbsp;&nbsp; $1549439 |
| Net investment income (loss) | &nbsp;&nbsp; $(704556)<br>|
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $17628951 |
| Affiliated issuers | &nbsp;&nbsp; (351)<br>|
| Foreign currency | &nbsp;&nbsp; (3737)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $17624863 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $14048032 |
| Affiliated issuers | &nbsp;&nbsp; (27)<br>|
| Net unrealized gain (loss) | &nbsp;&nbsp; $14048005 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $31672868 |
| Change in net assets from operations | &nbsp;&nbsp; $30968312 |

---

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $(704556)<br>| &nbsp;&nbsp; $(1261726)<br>|
| Net realized gain (loss) | 17624863 | &nbsp;&nbsp; 61606310 |
| Net unrealized gain (loss) | 14048005 | &nbsp;&nbsp; (11551101)<br>|
| Change in net assets from operations | $30968312 | &nbsp;&nbsp; $48793483 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(23781131)<br>|
| Change in net assets from fund share transactions | $(17310610)<br>| &nbsp;&nbsp; $(15304237)<br>|
| Total change in net assets | $13657702 | &nbsp;&nbsp; $9708115 |
| **Net assets** |  |  |
| At beginning of period | 356460356 | &nbsp;&nbsp; 346752241 |
| At end of period | $370118058 | &nbsp;&nbsp; $356460356 |

---

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $9.20 | &nbsp;&nbsp; $8.57 | &nbsp;&nbsp; $7.16 | &nbsp;&nbsp; $11.72 | &nbsp;&nbsp; $12.64 | &nbsp;&nbsp; $9.96 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $(0.01)<br>| &nbsp;&nbsp; $(0.02)<br>| &nbsp;&nbsp; $(0.01)<br>| &nbsp;&nbsp; $(0.01)<br>| &nbsp;&nbsp; $(0.05)<br>| &nbsp;&nbsp; $(0.03)<br>|
| Net realized and unrealized gain (loss) | 0.80 | &nbsp;&nbsp;&nbsp;&nbsp;1.25 | &nbsp;&nbsp;&nbsp;&nbsp;1.53 | &nbsp;&nbsp; (3.28)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.78 | &nbsp;&nbsp;&nbsp;&nbsp;3.53 |
| Total from investment operations | $0.79 | &nbsp;&nbsp; $1.23 | &nbsp;&nbsp; $1.52 | &nbsp;&nbsp; $(3.29)<br>| &nbsp;&nbsp; $1.73 | &nbsp;&nbsp; $3.50 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | &nbsp;&nbsp; $(0.60)<br>| &nbsp;&nbsp; $(0.11)<br>| &nbsp;&nbsp; $(1.27)<br>| &nbsp;&nbsp; $(2.65)<br>| &nbsp;&nbsp; $(0.82)<br>|
| Net asset value, end of period (x) | $9.99 | &nbsp;&nbsp; $9.20 | &nbsp;&nbsp; $8.57 | &nbsp;&nbsp; $7.16 | &nbsp;&nbsp; $11.72 | &nbsp;&nbsp; $12.64 |
| Total return (%) (k)(r)(s)(x) | 8.59<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;14.72 | &nbsp;&nbsp;&nbsp;&nbsp;21.32 | &nbsp;&nbsp; (28.70)<br>| &nbsp;&nbsp;&nbsp;&nbsp;14.11 | &nbsp;&nbsp;&nbsp;&nbsp;36.48 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.81<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.81 | &nbsp;&nbsp;&nbsp;&nbsp;0.81 | &nbsp;&nbsp;&nbsp;&nbsp;0.81 | &nbsp;&nbsp;&nbsp;&nbsp;0.81 | &nbsp;&nbsp;&nbsp;&nbsp;0.81 |
| Expenses after expense reductions | 0.80<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 |
| Net investment income (loss) | (0.31)(a)<br>| &nbsp;&nbsp; (0.26)<br>| &nbsp;&nbsp; (0.07)<br>| &nbsp;&nbsp; (0.17)<br>| &nbsp;&nbsp; (0.44)<br>| &nbsp;&nbsp; (0.26)<br>|
| Portfolio turnover rate | 28<br> (n)<br>| &nbsp;&nbsp; 44 | &nbsp;&nbsp; 31 | &nbsp;&nbsp; 27 | &nbsp;&nbsp; 18 | &nbsp;&nbsp; 40 |
| Net assets at end of period (000 omitted) | $233210 | &nbsp;&nbsp; $225230 | &nbsp;&nbsp; $226799 | &nbsp;&nbsp; $210790 | &nbsp;&nbsp; $306174 | &nbsp;&nbsp; $311988 |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $7.86 | &nbsp;&nbsp; $7.42 | &nbsp;&nbsp; $6.23 | &nbsp;&nbsp; $10.43 | &nbsp;&nbsp; $11.53 | &nbsp;&nbsp; $9.17 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $(0.02)<br>| &nbsp;&nbsp; $(0.04)<br>| &nbsp;&nbsp; $(0.02)<br>| &nbsp;&nbsp; $(0.03)<br>| &nbsp;&nbsp; $(0.08)<br>| &nbsp;&nbsp; $(0.05)<br>|
| Net realized and unrealized gain (loss) | 0.68 | &nbsp;&nbsp;&nbsp;&nbsp;1.08 | &nbsp;&nbsp;&nbsp;&nbsp;1.32 | &nbsp;&nbsp; (2.90)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.63 | &nbsp;&nbsp;&nbsp;&nbsp;3.23 |
| Total from investment operations | $0.66 | &nbsp;&nbsp; $1.04 | &nbsp;&nbsp; $1.30 | &nbsp;&nbsp; $(2.93)<br>| &nbsp;&nbsp; $1.55 | &nbsp;&nbsp; $3.18 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | &nbsp;&nbsp; $(0.60)<br>| &nbsp;&nbsp; $(0.11)<br>| &nbsp;&nbsp; $(1.27)<br>| &nbsp;&nbsp; $(2.65)<br>| &nbsp;&nbsp; $(0.82)<br>|
| Net asset value, end of period (x) | $8.52 | &nbsp;&nbsp; $7.86 | &nbsp;&nbsp; $7.42 | &nbsp;&nbsp; $6.23 | &nbsp;&nbsp; $10.43 | &nbsp;&nbsp; $11.53 |
| Total return (%) (k)(r)(s)(x) | 8.40<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;14.44 | &nbsp;&nbsp;&nbsp;&nbsp;20.97 | &nbsp;&nbsp; (28.79)<br>| &nbsp;&nbsp;&nbsp;&nbsp;13.88 | &nbsp;&nbsp;&nbsp;&nbsp;36.12 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.06<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.06 | &nbsp;&nbsp;&nbsp;&nbsp;1.06 | &nbsp;&nbsp;&nbsp;&nbsp;1.06 | &nbsp;&nbsp;&nbsp;&nbsp;1.06 | &nbsp;&nbsp;&nbsp;&nbsp;1.06 |
| Expenses after expense reductions | 1.05<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 |
| Net investment income (loss) | (0.56)(a)<br>| &nbsp;&nbsp; (0.51)<br>| &nbsp;&nbsp; (0.32)<br>| &nbsp;&nbsp; (0.41)<br>| &nbsp;&nbsp; (0.68)<br>| &nbsp;&nbsp; (0.51)<br>|
| Portfolio turnover rate | 28<br> (n)<br>| &nbsp;&nbsp; 44 | &nbsp;&nbsp; 31 | &nbsp;&nbsp; 27 | &nbsp;&nbsp; 18 | &nbsp;&nbsp; 40 |
| Net assets at end of period (000 omitted) | $136908 | &nbsp;&nbsp; $131231 | &nbsp;&nbsp; $119953 | &nbsp;&nbsp; $104914 | &nbsp;&nbsp; $142517 | &nbsp;&nbsp; $131845 |

---

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

*Financial Highlights - continued*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Mid Cap Growth Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Mid Cap Growth Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or

------

MFS Mid Cap Growth Series

*Notes to Financial Statements (unaudited) - continued* 

market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities: |  |  |  |  |
| United States | $326055261 | $— | $— | $326055261 |
| Canada | 13573943 | 0 |  | 13573943 |
| Sweden | 12337292 |  |  | 12337292 |
| South Korea | 5569564 |  |  | 5569564 |
| Denmark | 5331614 |  |  | 5331614 |
| Netherlands | 2082403 |  |  | 2082403 |
| Israel | 1955201 |  |  | 1955201 |
| Switzerland | 1772045 |  |  | 1772045 |
| United Kingdom | 1092066 |  |  | 1092066 |
| Investment Companies | 1788325 |  |  | 1788325 |
| Total | $371557714 | $0 | $— | $371557714 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Security Loans** — Under its Securities Lending Agency Agreement with the fund, Goldman Sachs Agency Lending, as lending agent, loans the securities of the fund to certain qualified institutions (the "Borrowers") approved by the fund. Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returned within the earlier of the standard trade settlement period for such securities or within five business days. The loans are collateralized by cash and/or U.S. government securities in an amount typically at least equal to the market value of the securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of the loaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund on the next business day. The lending agent provides the fund with indemnification against Borrower default. In the event of Borrower default, the lending agent will, for the benefit of the fund, either purchase securities identical to those loaned or pay the fund the market value of the loaned securities. In return, the lending agent assumes the fund's rights to the related collateral. If the collateral value is less than the cost to purchase identical securities or the cash needed to pay their market value, the lending agent is responsible for the shortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment for which the fund bears the risk of loss. At period end, the fund had investment securities on loan, all of which were classified as equity securities in the fund's

------

MFS Mid Cap Growth Series

*Notes to Financial Statements (unaudited) - continued* 

Portfolio of Investments, with a fair value of $304,992. The fair value of the fund's investment securities on loan and a related liability of $326,400 for the obligation to return cash collateral received on securities loaned are both presented gross in the Statement of Assets and Liabilities. The collateral on securities loaned exceeded the value of securities on loan at period end. The liability for cash collateral for securities loaned is carried at fair value, which is categorized as level 2 within the fair value hierarchy. A portion of the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated between the fund and the lending agent. On loans collateralized by U.S. government securities, a fee is received from the Borrower, and is allocated between the fund and the lending agent. Income from securities lending is separately reported in the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the same manner as other dividend and interest income.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Interest income is recorded on the accrual basis. Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to net operating losses and wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Long-term capital gains | &nbsp;&nbsp; $23781131 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

------

MFS Mid Cap Growth Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $222623447 |
| Gross appreciation | &nbsp;&nbsp; 151840069 |
| Gross depreciation | &nbsp;&nbsp; (2905802)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $148934267 |
| <br>**As of 12/31/24** |  |
| Undistributed long-term capital gain | &nbsp;&nbsp; 61848767 |
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 135005604 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $14360498 |
| Service Class |  | &nbsp;&nbsp; 9420633 |
| Total | $— | &nbsp;&nbsp; $23781131 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion | 0.70% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $24,142, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.74% of the fund's average daily net assets.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $6,783, which equated to 0.0039% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $699.

------

MFS Mid Cap Growth Series

*Notes to Financial Statements (unaudited) - continued* 

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0163% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 3 shares of the Service Class for an amount of $23.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in purchase and sale transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $582,330 and $59,490, respectively. The sales transactions resulted in net realized gains (losses) of $(33,654).

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $8,214, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $98,707,858 and $115,253,523, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 2453594 | &nbsp;&nbsp; $21275965 | &nbsp;&nbsp; 2711815 | &nbsp;&nbsp; $25037654 |
| Service Class | 1948521 | &nbsp;&nbsp; 15241781 | &nbsp;&nbsp; 3219021 | &nbsp;&nbsp; 25366970 |
|  | 4402115 | &nbsp;&nbsp; $36517746 | &nbsp;&nbsp; 5930836 | &nbsp;&nbsp; $50404624 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 1638265 | &nbsp;&nbsp; $14269292 |
| Service Class |  |  | &nbsp;&nbsp; 1266214 | &nbsp;&nbsp; 9420633 |
|  |  | $— | &nbsp;&nbsp; 2904479 | &nbsp;&nbsp; $23689925 |
| Shares reacquired |  |  |  |  |
| Initial Class | (3583073)<br>| &nbsp;&nbsp; $(33224180)<br>| &nbsp;&nbsp; (6336813)<br>| &nbsp;&nbsp; $(58094072)<br>|
| Service Class | (2579172)<br>| &nbsp;&nbsp; (20604176)<br>| &nbsp;&nbsp; (3956640)<br>| &nbsp;&nbsp; (31304714)<br>|
|  | (6162245)<br>| &nbsp;&nbsp; $(53828356)<br>| &nbsp;&nbsp; (10293453)<br>| &nbsp;&nbsp; $(89398786)<br>|
| Net change |  |  |  |  |
| Initial Class | (1129479)<br>| &nbsp;&nbsp; $(11948215)<br>| &nbsp;&nbsp; (1986733)<br>| &nbsp;&nbsp; $(18787126)<br>|
| Service Class | (630651)<br>| &nbsp;&nbsp; (5362395)<br>| &nbsp;&nbsp; 528595 | &nbsp;&nbsp; 3482889 |
|  | (1760130)<br>| &nbsp;&nbsp; $(17310610)<br>| &nbsp;&nbsp; (1458138)<br>| &nbsp;&nbsp; $(15304237)<br>|

---

------

MFS Mid Cap Growth Series

*Notes to Financial Statements (unaudited) - continued* 

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio, the MFS Growth Allocation Portfolio, and the MFS Conservative Allocation Portfolio were the owners of record of approximately 18%, 8%, and 3%, respectively, of the value of outstanding voting shares of the fund.

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $839 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $2335732 | &nbsp;&nbsp; $37707325 | &nbsp;&nbsp; $38580754 | &nbsp;&nbsp; $(351)<br>| &nbsp;&nbsp; $(27)<br>| &nbsp;&nbsp; $1461925 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $105349 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Mid Cap Growth Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Mid Cap Growth Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Mid Cap Growth Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Global Equity Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Global Equity Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 97.7% | Common Stocks – 97.7% | Common Stocks – 97.7% |
| Aerospace & Defense – 5.5% | Aerospace & Defense – 5.5% |  |
| Honeywell International, Inc. | 4331 | &nbsp;&nbsp; $1008603 |
| Melrose Industries PLC | 101106 | &nbsp;&nbsp; 736661 |
| MTU Aero Engines Holding AG | 881 | &nbsp;&nbsp; 391449 |
| Rolls-Royce Holdings PLC | 39894 | &nbsp;&nbsp; 529862 |
|  |  | &nbsp;&nbsp; $2666575 |
| Airlines – 0.9% | Airlines – 0.9% |  |
| Aena SME S.A. | 16320 | &nbsp;&nbsp; $435619 |
| Alcoholic Beverages – 6.0% | Alcoholic Beverages – 6.0% |  |
| Carlsberg A.S., "B" | 2085 | &nbsp;&nbsp; $295414 |
| Davide Campari-Milano N.V. | 84188 | &nbsp;&nbsp; 566257 |
| Diageo PLC | 23104 | &nbsp;&nbsp; 579726 |
| Heineken N.V. | 7757 | &nbsp;&nbsp; 676348 |
| Pernod Ricard S.A. | 7751 | &nbsp;&nbsp; 772423 |
|  |  | &nbsp;&nbsp; $2890168 |
| Apparel Manufacturers – 4.2% | Apparel Manufacturers – 4.2% |  |
| Burberry Group PLC (a) | 15545 | &nbsp;&nbsp; $252213 |
| Compagnie Financiere Richemont S.A. | 3954 | &nbsp;&nbsp; 744754 |
| Hermes International | 90 | &nbsp;&nbsp; 243730 |
| LVMH Moet Hennessy Louis Vuitton SE | 1449 | &nbsp;&nbsp; 758866 |
|  |  | &nbsp;&nbsp; $1999563 |
| Automotive – 0.6% | Automotive – 0.6% |  |
| Aptiv PLC (a) | 4590 | &nbsp;&nbsp; $313130 |
| Broadcasting – 1.5% | Broadcasting – 1.5% |  |
| Omnicom Group, Inc. | 1337 | &nbsp;&nbsp; $96184 |
| Walt Disney Co. | 3812 | &nbsp;&nbsp; 472726 |
| WPP Group PLC | 23039 | &nbsp;&nbsp; 162107 |
|  |  | &nbsp;&nbsp; $731017 |
| Brokerage & Asset Managers – 4.2% | Brokerage & Asset Managers – 4.2% |  |
| Charles Schwab Corp. | 13417 | &nbsp;&nbsp; $1224167 |
| Deutsche Boerse AG | 1079 | &nbsp;&nbsp; 351943 |
| London Stock Exchange Group PLC | 2926 | &nbsp;&nbsp; 427141 |
|  |  | &nbsp;&nbsp; $2003251 |
| Business Services – 8.0% | Business Services – 8.0% |  |
| Accenture PLC, "A" | 1940 | &nbsp;&nbsp; $579847 |
| Brenntag AG | 2380 | &nbsp;&nbsp; 157558 |
| Cognizant Technology Solutions Corp., "A" | 3236 | &nbsp;&nbsp; 252505 |
| Compass Group PLC | 6522 | &nbsp;&nbsp; 220856 |
| Equifax, Inc. | 931 | &nbsp;&nbsp; 241473 |
| Experian PLC | 10003 | &nbsp;&nbsp; 515173 |
| Fidelity National Information Services, Inc. | 5551 | &nbsp;&nbsp; 451907 |
| Fiserv, Inc. (a) | 2884 | &nbsp;&nbsp; 497230 |
| Intertek Group PLC | 4986 | &nbsp;&nbsp; 324407 |

---

VGEFS-SEM

------

MFS Global Equity Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Business Services – continued | Business Services – continued |  |
| TransUnion | 6618 | &nbsp;&nbsp; $582384 |
|  |  | &nbsp;&nbsp; $3823340 |
| Computer Software – 7.0% | Computer Software – 7.0% |  |
| Check Point Software Technologies Ltd. (a) | 2637 | &nbsp;&nbsp; $583436 |
| Microsoft Corp. | 3128 | &nbsp;&nbsp; 1555899 |
| Oracle Corp. | 3512 | &nbsp;&nbsp; 767829 |
| Salesforce, Inc. | 1712 | &nbsp;&nbsp; 466845 |
|  |  | &nbsp;&nbsp; $3374009 |
| Computer Software - Systems – 4.4% | Computer Software - Systems – 4.4% |  |
| Amadeus IT Group S.A. | 10791 | &nbsp;&nbsp; $908602 |
| Cap Gemini S.A. | 4968 | &nbsp;&nbsp; 848841 |
| Samsung Electronics Co. Ltd. | 7967 | &nbsp;&nbsp; 353013 |
|  |  | &nbsp;&nbsp; $2110456 |
| Construction – 1.8% | Construction – 1.8% |  |
| CRH PLC | 3666 | &nbsp;&nbsp; $336539 |
| James Hardie Industries PLC (a)(l) | 19138 | &nbsp;&nbsp; 514621 |
| James Hardie Industries PLC (a) | 535 | &nbsp;&nbsp; 14223 |
|  |  | &nbsp;&nbsp; $865383 |
| Consumer Products – 1.9% | Consumer Products – 1.9% |  |
| International Flavors & Fragrances, Inc. | 6350 | &nbsp;&nbsp; $467042 |
| Reckitt Benckiser Group PLC | 6680 | &nbsp;&nbsp; 454339 |
|  |  | &nbsp;&nbsp; $921381 |
| Electrical Equipment – 5.0% | Electrical Equipment – 5.0% |  |
| Amphenol Corp., "A" | 4331 | &nbsp;&nbsp; $427686 |
| Legrand S.A. | 6006 | &nbsp;&nbsp; 802987 |
| Schneider Electric SE | 4481 | &nbsp;&nbsp; 1191862 |
|  |  | &nbsp;&nbsp; $2422535 |
| Electronics – 1.1% | Electronics – 1.1% |  |
| Hoya Corp. | 2600 | &nbsp;&nbsp; $309732 |
| Microchip Technology, Inc. | 2830 | &nbsp;&nbsp; 199147 |
|  |  | &nbsp;&nbsp; $508879 |
| Food & Beverages – 1.4% | Food & Beverages – 1.4% |  |
| Nestle S.A. | 6830 | &nbsp;&nbsp; $678567 |
| Gaming & Lodging – 1.1% | Gaming & Lodging – 1.1% |  |
| Marriott International, Inc., "A" | 1353 | &nbsp;&nbsp; $369653 |
| Whitbread PLC | 4382 | &nbsp;&nbsp; 169802 |
|  |  | &nbsp;&nbsp; $539455 |
| Insurance – 3.4% | Insurance – 3.4% |  |
| Aon PLC | 1541 | &nbsp;&nbsp; $549767 |
| Willis Towers Watson PLC | 3594 | &nbsp;&nbsp; 1101561 |
|  |  | &nbsp;&nbsp; $1651328 |
| Interactive Media Services – 2.2% | Interactive Media Services – 2.2% |  |
| Alphabet, Inc., "A" | 6066 | &nbsp;&nbsp; $1069011 |

---

------

MFS Global Equity Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Internet – 0.7% | Internet – 0.7% |  |
| eBay, Inc. | 4356 | &nbsp;&nbsp; $324348 |
| Machinery & Tools – 0.7% | Machinery & Tools – 0.7% |  |
| Carrier Global Corp. | 4860 | &nbsp;&nbsp; $355703 |
| Major Banks – 4.7% | Major Banks – 4.7% |  |
| Erste Group Bank AG | 4139 | &nbsp;&nbsp; $352501 |
| Goldman Sachs Group, Inc. | 1005 | &nbsp;&nbsp; 711289 |
| National Bank of Greece S.A. | 26226 | &nbsp;&nbsp; 334571 |
| UBS Group AG | 24780 | &nbsp;&nbsp; 838544 |
|  |  | &nbsp;&nbsp; $2236905 |
| Medical Equipment – 11.1% | Medical Equipment – 11.1% |  |
| Abbott Laboratories | 3830 | &nbsp;&nbsp; $520918 |
| Becton, Dickinson and Co. | 5410 | &nbsp;&nbsp; 931873 |
| Cooper Companies, Inc. (a) | 6449 | &nbsp;&nbsp; 458911 |
| Medtronic PLC | 13119 | &nbsp;&nbsp; 1143583 |
| Olympus Corp. | 30200 | &nbsp;&nbsp; 359661 |
| STERIS PLC | 2513 | &nbsp;&nbsp; 603673 |
| Thermo Fisher Scientific, Inc. | 2069 | &nbsp;&nbsp; 838897 |
| Waters Corp. (a) | 1311 | &nbsp;&nbsp; 457591 |
|  |  | &nbsp;&nbsp; $5315107 |
| Other Banks & Diversified Financials – 5.6% | Other Banks & Diversified Financials – 5.6% |  |
| American Express Co. | 2515 | &nbsp;&nbsp; $802235 |
| Grupo Financiero Banorte S.A. de C.V. | 14263 | &nbsp;&nbsp; 130373 |
| Julius Baer Group Ltd. | 2765 | &nbsp;&nbsp; 186924 |
| Visa, Inc., "A" | 4478 | &nbsp;&nbsp; 1589914 |
|  |  | &nbsp;&nbsp; $2709446 |
| Pharmaceuticals – 3.0% | Pharmaceuticals – 3.0% |  |
| Merck KGaA | 4578 | &nbsp;&nbsp; $593192 |
| Roche Holding AG | 2572 | &nbsp;&nbsp; 837614 |
|  |  | &nbsp;&nbsp; $1430806 |
| Railroad & Shipping – 3.9% | Railroad & Shipping – 3.9% |  |
| Canadian National Railway Co. | 5455 | &nbsp;&nbsp; $567538 |
| Canadian Pacific Kansas City Ltd. (l) | 9882 | &nbsp;&nbsp; 783346 |
| Union Pacific Corp. | 2222 | &nbsp;&nbsp; 511238 |
|  |  | &nbsp;&nbsp; $1862122 |
| Specialty Chemicals – 4.5% | Specialty Chemicals – 4.5% |  |
| Air Liquide S.A. | 2133 | &nbsp;&nbsp; $440051 |
| Air Products & Chemicals, Inc. | 1928 | &nbsp;&nbsp; 543812 |
| Akzo Nobel N.V. | 4332 | &nbsp;&nbsp; 303111 |
| Linde PLC | 1841 | &nbsp;&nbsp; 863761 |
|  |  | &nbsp;&nbsp; $2150735 |
| Telecom - Infrastructure – 1.1% | Telecom - Infrastructure – 1.1% |  |
| Cellnex Telecom S.A. | 13477 | &nbsp;&nbsp; $523089 |
| Telecom Services – 1.7% | Telecom Services – 1.7% |  |
| Comcast Corp., "A" | 22250 | &nbsp;&nbsp; $794102 |

---

------

MFS Global Equity Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Trucking – 0.5% | Trucking – 0.5% |  |
| United Parcel Service, Inc., "B" | 2175 | &nbsp;&nbsp; $219545 |
| **Total Common Stocks (Identified Cost, $25,447,071)** |  | &nbsp;&nbsp; **$46925575** |
| Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% |
| Money Market Funds – 0.4% | Money Market Funds – 0.4% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $207,103) | 207102 | &nbsp;&nbsp; $207122 |
| Collateral for Securities Loaned – 2.5% | Collateral for Securities Loaned – 2.5% | Collateral for Securities Loaned – 2.5% |
| JPMorgan U.S. Government Money Market Fund - Class IM Shares, 4.26% (j) (Identified Cost, $1,171,684) | 1171684 | &nbsp;&nbsp; $1171684 |
| Other Assets, Less Liabilities – (0.6)% |  | &nbsp;&nbsp; (286661) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$48017720** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $207,122 and $48,097,259, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(j) The rate quoted is the annualized seven-day yield of the fund at period end.

&nbsp;&nbsp;&nbsp;&nbsp;(l) A portion of this security is on loan. See Note 2 for additional information.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

**See Notes to Financial Statements**

------

MFS Global Equity Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

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| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value, including $1,142,939 of securities on loan (identified cost, $26,618,755) | &nbsp;&nbsp; $48097259 |
| Investments in affiliated issuers, at value (identified cost, $207,103) | &nbsp;&nbsp; 207122 |
| Cash | &nbsp;&nbsp; 2933 |
| Receivables for |  |
| Fund shares sold | &nbsp;&nbsp; 1453126 |
| Interest and dividends | &nbsp;&nbsp; 171549 |
| Receivable from investment adviser | &nbsp;&nbsp; 7357 |
| Other assets | &nbsp;&nbsp; 164 |
| Total assets | &nbsp;&nbsp; $49939510 |
| **Liabilities** |  |
| Payables for |  |
| Investments purchased | &nbsp;&nbsp; $655368 |
| Fund shares reacquired | &nbsp;&nbsp; 25770 |
| Collateral for securities loaned, at value | &nbsp;&nbsp; 1171684 |
| Payable to affiliates |  |
| Administrative services fee | &nbsp;&nbsp; 192 |
| Shareholder servicing costs | &nbsp;&nbsp; 106 |
| Distribution and/or service fees | &nbsp;&nbsp; 278 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 489 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 67903 |
| Total liabilities | &nbsp;&nbsp; $1921790 |
| Net assets | &nbsp;&nbsp; $48017720 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $16083369 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 31934351 |
| Net assets | &nbsp;&nbsp; $48017720 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 2099919 |

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| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $36669464 | &nbsp;&nbsp;&nbsp; 1598916 | &nbsp;&nbsp;&nbsp; $22.93 |
| Service Class | &nbsp;&nbsp;&nbsp; 11348256 | &nbsp;&nbsp;&nbsp; 501003 | &nbsp;&nbsp;&nbsp;&nbsp;22.65 |

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**See Notes to Financial Statements**

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MFS Global Equity Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

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| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $532312 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 7799 |
| Income on securities loaned | &nbsp;&nbsp; 616 |
| Other | &nbsp;&nbsp; 36 |
| Foreign taxes withheld | &nbsp;&nbsp; (40738)<br>|
| Total investment income | &nbsp;&nbsp; $500025 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $204624 |
| Distribution and/or service fees | &nbsp;&nbsp; 11935 |
| Shareholder servicing costs | &nbsp;&nbsp; 2288 |
| Administrative services fee | &nbsp;&nbsp; 8679 |
| Independent Trustees' compensation | &nbsp;&nbsp; 1504 |
| Custodian fee | &nbsp;&nbsp; 9120 |
| Shareholder communications | &nbsp;&nbsp; 3629 |
| Audit and tax fees | &nbsp;&nbsp; 36984 |
| Legal fees | &nbsp;&nbsp; 145 |
| Miscellaneous | &nbsp;&nbsp; 13817 |
| Total expenses | &nbsp;&nbsp; $292725 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (71390)<br>|
| Net expenses | &nbsp;&nbsp; $221335 |
| Net investment income (loss) | &nbsp;&nbsp; $278690 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $3309980 |
| Affiliated issuers | &nbsp;&nbsp; (9)<br>|
| Foreign currency | &nbsp;&nbsp; 1871 |
| Net realized gain (loss)  | &nbsp;&nbsp; $3311842 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $115934 |
| Affiliated issuers | &nbsp;&nbsp; 8 |
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 15040 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $130982 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $3442824 |
| Change in net assets from operations | &nbsp;&nbsp; $3721514 |

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**See Notes to Financial Statements**

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MFS Global Equity Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

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| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $278690 | &nbsp;&nbsp; $356652 |
| Net realized gain (loss) | 3311842 | &nbsp;&nbsp; 7007326 |
| Net unrealized gain (loss) | 130982 | &nbsp;&nbsp; (4442026)<br>|
| Change in net assets from operations | $3721514 | &nbsp;&nbsp; $2921952 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(3359613)<br>|
| Change in net assets from fund share transactions | $(2281446)<br>| &nbsp;&nbsp; $(5264917)<br>|
| Total change in net assets | $1440068 | &nbsp;&nbsp; $(5702578)<br>|
| **Net assets** |  |  |
| At beginning of period | 46577652 | &nbsp;&nbsp; 52280230 |
| At end of period | $48017720 | &nbsp;&nbsp; $46577652 |

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**See Notes to Financial Statements**

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MFS Global Equity Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $21.16 | &nbsp;&nbsp; $21.47 | &nbsp;&nbsp; $19.82 | &nbsp;&nbsp; $26.90 | &nbsp;&nbsp; $24.57 | &nbsp;&nbsp; $22.79 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.14 | &nbsp;&nbsp; $0.17 | &nbsp;&nbsp; $0.19 | &nbsp;&nbsp; $0.16 | &nbsp;&nbsp; $0.12 | &nbsp;&nbsp; $0.16 |
| Net realized and unrealized gain (loss) | 1.63 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;2.55 | &nbsp;&nbsp; (4.91)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.07 | &nbsp;&nbsp;&nbsp;&nbsp;2.73 |
| Total from investment operations | $1.77 | &nbsp;&nbsp; $1.21 | &nbsp;&nbsp; $2.74 | &nbsp;&nbsp; $(4.75)<br>| &nbsp;&nbsp; $4.19 | &nbsp;&nbsp; $2.89 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.21)<br>| &nbsp;&nbsp; $(0.17)<br>| &nbsp;&nbsp; $(0.12)<br>| &nbsp;&nbsp; $(0.17)<br>| &nbsp;&nbsp; $(0.26)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.31)<br>| &nbsp;&nbsp; (0.92)<br>| &nbsp;&nbsp; (2.21)<br>| &nbsp;&nbsp; (1.69)<br>| &nbsp;&nbsp; (0.85)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.52)<br>| &nbsp;&nbsp; $(1.09)<br>| &nbsp;&nbsp; $(2.33)<br>| &nbsp;&nbsp; $(1.86)<br>| &nbsp;&nbsp; $(1.11)<br>|
| Net asset value, end of period (x) | $22.93 | &nbsp;&nbsp; $21.16 | &nbsp;&nbsp; $21.47 | &nbsp;&nbsp; $19.82 | &nbsp;&nbsp; $26.90 | &nbsp;&nbsp; $24.57 |
| Total return (%) (k)(r)(s)(x) | 8.36<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;5.58 | &nbsp;&nbsp;&nbsp;&nbsp;14.18 | &nbsp;&nbsp; (17.73)<br>| &nbsp;&nbsp;&nbsp;&nbsp;17.21 | &nbsp;&nbsp;&nbsp;&nbsp;13.29 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.23<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.22 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.13 | &nbsp;&nbsp;&nbsp;&nbsp;1.16 |
| Expenses after expense reductions | 0.92<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.92 | &nbsp;&nbsp;&nbsp;&nbsp;0.92 | &nbsp;&nbsp;&nbsp;&nbsp;0.92 | &nbsp;&nbsp;&nbsp;&nbsp;0.92 | &nbsp;&nbsp;&nbsp;&nbsp;0.92 |
| Net investment income (loss) | 1.28(l)<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.76 | &nbsp;&nbsp;&nbsp;&nbsp;0.91 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 | &nbsp;&nbsp;&nbsp;&nbsp;0.45 | &nbsp;&nbsp;&nbsp;&nbsp;0.75 |
| Portfolio turnover rate | 10<br> (n)<br>| &nbsp;&nbsp; 20 | &nbsp;&nbsp; 9 | &nbsp;&nbsp; 7 | &nbsp;&nbsp; 12 | &nbsp;&nbsp; 12 |
| Net assets at end of period (000 omitted) | $36669 | &nbsp;&nbsp; $36772 | &nbsp;&nbsp; $42288 | &nbsp;&nbsp; $39840 | &nbsp;&nbsp; $51966 | &nbsp;&nbsp; $46879 |

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**See Notes to Financial Statements**

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MFS Global Equity Series

*Financial Highlights - continued*

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $20.93 | &nbsp;&nbsp; $21.25 | &nbsp;&nbsp; $19.62 | &nbsp;&nbsp; $26.64 | &nbsp;&nbsp; $24.37 | &nbsp;&nbsp; $22.62 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.11 | &nbsp;&nbsp; $0.11 | &nbsp;&nbsp; $0.14 | &nbsp;&nbsp; $0.11 | &nbsp;&nbsp; $0.05 | &nbsp;&nbsp; $0.10 |
| Net realized and unrealized gain (loss) | 1.61 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;2.51 | &nbsp;&nbsp; (4.87)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.03 | &nbsp;&nbsp;&nbsp;&nbsp;2.71 |
| Total from investment operations | $1.72 | &nbsp;&nbsp; $1.15 | &nbsp;&nbsp; $2.65 | &nbsp;&nbsp; $(4.76)<br>| &nbsp;&nbsp; $4.08 | &nbsp;&nbsp; $2.81 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.16)<br>| &nbsp;&nbsp; $(0.10)<br>| &nbsp;&nbsp; $(0.05)<br>| &nbsp;&nbsp; $(0.12)<br>| &nbsp;&nbsp; $(0.21)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.31)<br>| &nbsp;&nbsp; (0.92)<br>| &nbsp;&nbsp; (2.21)<br>| &nbsp;&nbsp; (1.69)<br>| &nbsp;&nbsp; (0.85)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.47)<br>| &nbsp;&nbsp; $(1.02)<br>| &nbsp;&nbsp; $(2.26)<br>| &nbsp;&nbsp; $(1.81)<br>| &nbsp;&nbsp; $(1.06)<br>|
| Net asset value, end of period (x) | $22.65 | &nbsp;&nbsp; $20.93 | &nbsp;&nbsp; $21.25 | &nbsp;&nbsp; $19.62 | &nbsp;&nbsp; $26.64 | &nbsp;&nbsp; $24.37 |
| Total return (%) (k)(r)(s)(x) | 8.22<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;5.36 | &nbsp;&nbsp;&nbsp;&nbsp;13.88 | &nbsp;&nbsp; (17.94)<br>| &nbsp;&nbsp;&nbsp;&nbsp;16.88 | &nbsp;&nbsp;&nbsp;&nbsp;13.04 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.48<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.47 | &nbsp;&nbsp;&nbsp;&nbsp;1.42 | &nbsp;&nbsp;&nbsp;&nbsp;1.42 | &nbsp;&nbsp;&nbsp;&nbsp;1.38 | &nbsp;&nbsp;&nbsp;&nbsp;1.41 |
| Expenses after expense reductions | 1.17<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 |
| Net investment income (loss) | 1.03(l)<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.51 | &nbsp;&nbsp;&nbsp;&nbsp;0.66 | &nbsp;&nbsp;&nbsp;&nbsp;0.49 | &nbsp;&nbsp;&nbsp;&nbsp;0.19 | &nbsp;&nbsp;&nbsp;&nbsp;0.48 |
| Portfolio turnover rate | 10<br> (n)<br>| &nbsp;&nbsp; 20 | &nbsp;&nbsp; 9 | &nbsp;&nbsp; 7 | &nbsp;&nbsp; 12 | &nbsp;&nbsp; 12 |
| Net assets at end of period (000 omitted) | $11348 | &nbsp;&nbsp; $9806 | &nbsp;&nbsp; $9993 | &nbsp;&nbsp; $9473 | &nbsp;&nbsp; $14744 | &nbsp;&nbsp; $13469 |

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&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(l) Recognition of net investment income by the fund may be affected by the timing of
 the declaration of dividends by companies in which the fund invests and the actual annual net investment income ratio may differ.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

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MFS Global Equity Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Global Equity Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued. The fund invests in foreign securities. Investments in foreign securities are vulnerable to the effects of changes in the relative values of the local currency and the U.S. dollar and to the effects of changes in each country's market, economic, industrial, political, regulatory, geopolitical, environmental, public health, and other conditions.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and

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MFS Global Equity Series

*Notes to Financial Statements (unaudited) - continued* 

market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

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| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $46925575 | $— | $— | $46925575 |
| Investment Companies | 1378806 |  |  | 1378806 |
| Total | $48304381 | $— | $— | $48304381 |

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For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Security Loans** — Under its Securities Lending Agency Agreement with the fund, Goldman Sachs Agency Lending, as lending agent, loans the securities of the fund to certain qualified institutions (the "Borrowers") approved by the fund. Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returned within the earlier of the standard trade settlement period for such securities or within five business days. The loans are collateralized by cash and/or U.S. government securities in an amount typically at least equal to the market value of the securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of the loaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund on the next business day. The lending agent provides the fund with indemnification against Borrower default. In the event of Borrower default, the lending agent will, for the benefit of the fund, either purchase securities identical to those loaned or pay the fund the market value of the loaned securities. In return, the lending agent assumes the fund's rights to the related collateral. If the collateral value is less than the cost to purchase identical securities or the cash needed to pay their market value, the lending agent is responsible for the shortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment for which the fund bears the risk of loss. At period end, the fund had investment securities on loan, all of which were classified as equity securities in the fund's Portfolio of Investments, with a fair value of $1,142,939. The fair value of the fund's investment securities on loan and a related liability of $1,171,684 for the obligation to return cash collateral received on securities loaned are both presented gross in the Statement of Assets and Liabilities. The collateral on securities loaned exceeded the value of securities on loan at period end. The liability for cash collateral for securities loaned is carried at fair value, which is categorized as level 2 within the fair value hierarchy. A portion of the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated

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MFS Global Equity Series

*Notes to Financial Statements (unaudited) - continued* 

between the fund and the lending agent. On loans collateralized by U.S. government securities, a fee is received from the Borrower, and is allocated between the fund and the lending agent. Income from securities lending is separately reported in the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the same manner as other dividend and interest income.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

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| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $499362 |
| Long-term capital gains | &nbsp;&nbsp; 2860251 |
| Total distributions | &nbsp;&nbsp; $3359613 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

------

MFS Global Equity Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $27326186 |
| Gross appreciation | &nbsp;&nbsp; 21990806 |
| Gross depreciation | &nbsp;&nbsp; (1012611)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $20978195 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 549497 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 6806403 |
| Other temporary differences | &nbsp;&nbsp; (5316)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 20862253 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $2611975 |
| Service Class |  | &nbsp;&nbsp; 747638 |
| Total | $— | &nbsp;&nbsp; $3359613 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.90% |
| In excess of $1 billion and up to $2.5 billion | 0.75% |
| In excess of $2.5 billion | 0.65% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $3,161, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.89% of the fund's average daily net assets.

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses, such that total annual operating expenses do not exceed 0.92% of average daily net assets for the Initial Class shares and 1.17% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027. For the six months ended June 30, 2025, this reduction amounted to $68,229, which is included in the reduction of total expenses in the Statement of Operations.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and

------

MFS Global Equity Series

*Notes to Financial Statements (unaudited) - continued* 

variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $2,138, which equated to 0.0094% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $150.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0382% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $4,601,444 and $7,357,298, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 79954 | &nbsp;&nbsp; $1728406 | &nbsp;&nbsp; 106934 | &nbsp;&nbsp; $2351455 |
| Service Class | 104789 | &nbsp;&nbsp; 2316629 | &nbsp;&nbsp; 182955 | &nbsp;&nbsp; 4003280 |
|  | 184743 | &nbsp;&nbsp; $4045035 | &nbsp;&nbsp; 289889 | &nbsp;&nbsp; $6354735 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 122284 | &nbsp;&nbsp; $2611975 |
| Service Class |  |  | &nbsp;&nbsp; 35366 | &nbsp;&nbsp; 747638 |
|  |  | $— | &nbsp;&nbsp; 157650 | &nbsp;&nbsp; $3359613 |
| Shares reacquired |  |  |  |  |
| Initial Class | (218434)<br>| &nbsp;&nbsp; $(4770946)<br>| &nbsp;&nbsp; (461682)<br>| &nbsp;&nbsp; $(10187823)<br>|
| Service Class | (72292)<br>| &nbsp;&nbsp; (1555535)<br>| &nbsp;&nbsp; (220008)<br>| &nbsp;&nbsp; (4791442)<br>|
|  | (290726)<br>| &nbsp;&nbsp; $(6326481)<br>| &nbsp;&nbsp; (681690)<br>| &nbsp;&nbsp; $(14979265)<br>|
| Net change |  |  |  |  |
| Initial Class | (138480)<br>| &nbsp;&nbsp; $(3042540)<br>| &nbsp;&nbsp; (232464)<br>| &nbsp;&nbsp; $(5224393)<br>|
| Service Class | 32497 | &nbsp;&nbsp; 761094 | &nbsp;&nbsp; (1687)<br>| &nbsp;&nbsp; (40524)<br>|
|  | (105983)<br>| &nbsp;&nbsp; $(2281446)<br>| &nbsp;&nbsp; (234151)<br>| &nbsp;&nbsp; $(5264917)<br>|

---

------

MFS Global Equity Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $111 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $199383 | &nbsp;&nbsp; $4323730 | &nbsp;&nbsp; $4315990 | &nbsp;&nbsp; $(9)<br>| &nbsp;&nbsp; $8 | &nbsp;&nbsp; $207122 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $7799 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Global Equity Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Global Equity Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Global Equity Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Growth Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Growth Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 99.8% | Common Stocks – 99.8% | Common Stocks – 99.8% |
| Aerospace & Defense – 3.2% | Aerospace & Defense – 3.2% |  |
| Curtiss-Wright Corp. | 9284 | &nbsp;&nbsp; $4535698 |
| General Electric Co. | 106114 | &nbsp;&nbsp; 27312683 |
| Howmet Aerospace, Inc. | 212238 | &nbsp;&nbsp; 39503859 |
|  |  | &nbsp;&nbsp; $71352240 |
| Apparel Manufacturers – 0.4% | Apparel Manufacturers – 0.4% |  |
| LVMH Moet Hennessy Louis Vuitton SE | 16723 | &nbsp;&nbsp; $8758117 |
| Broadcasting – 5.1% | Broadcasting – 5.1% |  |
| Netflix, Inc. (a) | 51199 | &nbsp;&nbsp; $68562117 |
| Spotify Technology S.A. (a) | 58251 | &nbsp;&nbsp; 44698322 |
|  |  | &nbsp;&nbsp; $113260439 |
| Brokerage & Asset Managers – 3.6% | Brokerage & Asset Managers – 3.6% |  |
| Apollo Global Management, Inc. | 72442 | &nbsp;&nbsp; $10277347 |
| Ares Management Co. | 91788 | &nbsp;&nbsp; 15897682 |
| KKR & Co., Inc. | 259365 | &nbsp;&nbsp; 34503326 |
| LPL Financial Holdings, Inc. | 16800 | &nbsp;&nbsp; 6299496 |
| NASDAQ, Inc. | 162701 | &nbsp;&nbsp; 14548723 |
|  |  | &nbsp;&nbsp; $81526574 |
| Business Services – 2.9% | Business Services – 2.9% |  |
| CoStar Group, Inc. (a) | 117898 | &nbsp;&nbsp; $9478999 |
| Fiserv, Inc. (a) | 47818 | &nbsp;&nbsp; 8244301 |
| MSCI, Inc. | 8347 | &nbsp;&nbsp; 4814049 |
| TransUnion | 231732 | &nbsp;&nbsp; 20392416 |
| Verisk Analytics, Inc., "A" | 72935 | &nbsp;&nbsp; 22719253 |
|  |  | &nbsp;&nbsp; $65649018 |
| Computer Software – 19.2% | Computer Software – 19.2% |  |
| AppLovin Corp. (a) | 24315 | &nbsp;&nbsp; $8512195 |
| Atlassian Corp. (a) | 83223 | &nbsp;&nbsp; 16901759 |
| Autodesk, Inc. (a) | 102000 | &nbsp;&nbsp; 31576140 |
| Cadence Design Systems, Inc. (a) | 61042 | &nbsp;&nbsp; 18810092 |
| CrowdStrike Holdings, Inc. (a) | 23265 | &nbsp;&nbsp; 11849097 |
| Datadog, Inc., "A" (a) | 55498 | &nbsp;&nbsp; 7455046 |
| Guidewire Software, Inc. (a) | 53955 | &nbsp;&nbsp; 12703705 |
| Microsoft Corp. | 570544 | &nbsp;&nbsp; 283794291 |
| SAP SE | 43098 | &nbsp;&nbsp; 13105583 |
| ServiceNow, Inc. (a) | 17367 | &nbsp;&nbsp; 17854666 |
| Synopsys, Inc. (a) | 10915 | &nbsp;&nbsp; 5595902 |
|  |  | &nbsp;&nbsp; $428158476 |
| Computer Software - Systems – 4.8% | Computer Software - Systems – 4.8% |  |
| Apple, Inc. | 484345 | &nbsp;&nbsp; $99373064 |
| Shopify, Inc. (a) | 73746 | &nbsp;&nbsp; 8506601 |
|  |  | &nbsp;&nbsp; $107879665 |
| Construction – 1.0% | Construction – 1.0% |  |
| Vulcan Materials Co. | 81994 | &nbsp;&nbsp; $21385675 |

---

VEGFS-SEM

------

MFS Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Electrical Equipment – 1.9% | Electrical Equipment – 1.9% |  |
| Amphenol Corp., "A" | 422799 | &nbsp;&nbsp; $41751401 |
| Electronics – 12.4% | Electronics – 12.4% |  |
| ASML Holding N.V., ADR | 20550 | &nbsp;&nbsp; $16468564 |
| Broadcom, Inc. | 107325 | &nbsp;&nbsp; 29584136 |
| KLA Corp. | 16444 | &nbsp;&nbsp; 14729549 |
| NVIDIA Corp. | 1272799 | &nbsp;&nbsp; 201089514 |
| Taiwan Semiconductor Manufacturing Co. Ltd., ADR | 68134 | &nbsp;&nbsp; 15431670 |
|  |  | &nbsp;&nbsp; $277303433 |
| Energy - Renewables – 1.6% | Energy - Renewables – 1.6% |  |
| GE Vernova, Inc. | 65785 | &nbsp;&nbsp; $34810133 |
| Gaming & Lodging – 1.0% | Gaming & Lodging – 1.0% |  |
| Hilton Worldwide Holdings, Inc. | 81082 | &nbsp;&nbsp; $21595380 |
| Health Maintenance Organizations – 0.3% | Health Maintenance Organizations – 0.3% |  |
| Cigna Group | 22869 | &nbsp;&nbsp; $7560034 |
| Insurance – 0.7% | Insurance – 0.7% |  |
| Arthur J. Gallagher & Co. | 49536 | &nbsp;&nbsp; $15857464 |
| Interactive Media Services – 11.3% | Interactive Media Services – 11.3% |  |
| Alphabet, Inc., "A" | 484893 | &nbsp;&nbsp; $85452693 |
| Meta Platforms, Inc., "A" | 226299 | &nbsp;&nbsp; 167029029 |
|  |  | &nbsp;&nbsp; $252481722 |
| Leisure & Toys – 1.0% | Leisure & Toys – 1.0% |  |
| Take-Two Interactive Software, Inc. (a) | 90584 | &nbsp;&nbsp; $21998324 |
| Machinery & Tools – 2.7% | Machinery & Tools – 2.7% |  |
| Eaton Corp. PLC | 93011 | &nbsp;&nbsp; $33203997 |
| Roper Technologies, Inc. | 15646 | &nbsp;&nbsp; 8868779 |
| Trane Technologies PLC | 44557 | &nbsp;&nbsp; 19489677 |
|  |  | &nbsp;&nbsp; $61562453 |
| Major Banks – 0.2% | Major Banks – 0.2% |  |
| Goldman Sachs Group, Inc. | 7066 | &nbsp;&nbsp; $5000962 |
| Medical & Health Technology & Services – 0.5% | Medical & Health Technology & Services – 0.5% |  |
| Veeva Systems, Inc. (a) | 39327 | &nbsp;&nbsp; $11325389 |
| Medical Equipment – 5.0% | Medical Equipment – 5.0% |  |
| Abbott Laboratories | 107099 | &nbsp;&nbsp; $14566535 |
| Boston Scientific Corp. (a) | 320365 | &nbsp;&nbsp; 34410405 |
| Danaher Corp. | 22568 | &nbsp;&nbsp; 4458083 |
| DexCom, Inc. (a) | 88361 | &nbsp;&nbsp; 7713032 |
| Intuitive Surgical, Inc. (a) | 40406 | &nbsp;&nbsp; 21957024 |
| Medtronic PLC | 151738 | &nbsp;&nbsp; 13227001 |
| Thermo Fisher Scientific, Inc. | 36438 | &nbsp;&nbsp; 14774151 |
|  |  | &nbsp;&nbsp; $111106231 |
| Natural Gas - Pipeline – 1.0% | Natural Gas - Pipeline – 1.0% |  |
| Cheniere Energy, Inc. | 92263 | &nbsp;&nbsp; $22467886 |

---

------

MFS Growth Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Other Banks & Diversified Financials – 6.1% | Other Banks & Diversified Financials – 6.1% |  |
| Mastercard, Inc., "A" | 145382 | &nbsp;&nbsp; $81695961 |
| Moody's Corp. | 26396 | &nbsp;&nbsp; 13239970 |
| Visa, Inc., "A" | 116023 | &nbsp;&nbsp; 41193966 |
|  |  | &nbsp;&nbsp; $136129897 |
| Pharmaceuticals – 0.6% | Pharmaceuticals – 0.6% |  |
| Eli Lilly & Co. | 6612 | &nbsp;&nbsp; $5154252 |
| Vertex Pharmaceuticals, Inc. (a) | 20293 | &nbsp;&nbsp; 9034444 |
|  |  | &nbsp;&nbsp; $14188696 |
| Real Estate – 0.4% | Real Estate – 0.4% |  |
| CBRE Group, Inc., "A" (a) | 62094 | &nbsp;&nbsp; $8700611 |
| Restaurants – 0.8% | Restaurants – 0.8% |  |
| Chipotle Mexican Grill, Inc., "A" (a) | 85943 | &nbsp;&nbsp; $4825700 |
| Starbucks Corp. | 137561 | &nbsp;&nbsp; 12604714 |
|  |  | &nbsp;&nbsp; $17430414 |
| Specialty Chemicals – 1.0% | Specialty Chemicals – 1.0% |  |
| Linde PLC | 47308 | &nbsp;&nbsp; $22195967 |
| Specialty Stores – 8.4% | Specialty Stores – 8.4% |  |
| Amazon.com, Inc. (a) | 783871 | &nbsp;&nbsp; $171973459 |
| O'Reilly Automotive, Inc. (a) | 174472 | &nbsp;&nbsp; 15725161 |
|  |  | &nbsp;&nbsp; $187698620 |
| Tobacco – 1.8% | Tobacco – 1.8% |  |
| Philip Morris International, Inc. | 217035 | &nbsp;&nbsp; $39528585 |
| Utilities - Electric Power – 0.9% | Utilities - Electric Power – 0.9% |  |
| NextEra Energy, Inc. | 48742 | &nbsp;&nbsp; $3383670 |
| Vistra Corp. | 87558 | &nbsp;&nbsp; 16969616 |
|  |  | &nbsp;&nbsp; $20353286 |
| **Total Common Stocks (Identified Cost, $868,920,378)** |  | &nbsp;&nbsp; **$2229017092** |
| Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% |
| Money Market Funds – 0.4% | Money Market Funds – 0.4% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $9,155,727) | 9155722 | &nbsp;&nbsp; $9156638 |
| Other Assets, Less Liabilities – (0.2)% |  | &nbsp;&nbsp; (4170938) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$2234002792** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $9,156,638 and $2,229,017,092, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

The following abbreviations are used in this report and are defined: <br> ADR American Depositary Receipt

**See Notes to Financial Statements**

------

MFS Growth Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $868,920,378) | &nbsp;&nbsp; $2229017092 |
| Investments in affiliated issuers, at value (identified cost, $9,155,727) | &nbsp;&nbsp; 9156638 |
| Cash | &nbsp;&nbsp; 43207 |
| Receivables for |  |
| Fund shares sold | &nbsp;&nbsp; 341582 |
| Dividends | &nbsp;&nbsp; 562808 |
| Other assets | &nbsp;&nbsp; 2315 |
| Total assets | &nbsp;&nbsp; $2239123642 |
| **Liabilities** |  |
| Payables for |  |
| Fund shares reacquired | &nbsp;&nbsp; $4758547 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 164998 |
| Administrative services fee | &nbsp;&nbsp; 3182 |
| Shareholder servicing costs | &nbsp;&nbsp; 1096 |
| Distribution and/or service fees | &nbsp;&nbsp; 16839 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 7571 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 168617 |
| Total liabilities | &nbsp;&nbsp; $5120850 |
| Net assets | &nbsp;&nbsp; $2234002792 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $395875309 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 1838127483 |
| Net assets | &nbsp;&nbsp; $2234002792 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 29190816 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $1612653814 | &nbsp;&nbsp;&nbsp; 20533746 | &nbsp;&nbsp;&nbsp; $78.54 |
| Service Class | &nbsp;&nbsp;&nbsp; 621348978 | &nbsp;&nbsp;&nbsp; 8657070 | &nbsp;&nbsp;&nbsp;&nbsp;71.77 |

---

**See Notes to Financial Statements**

------

MFS Growth Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $5450200 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 510782 |
| Other | &nbsp;&nbsp; 17600 |
| Interest | &nbsp;&nbsp; 222 |
| Foreign taxes withheld | &nbsp;&nbsp; (64810)<br>|
| Total investment income | &nbsp;&nbsp; $5913994 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $7211749 |
| Distribution and/or service fees | &nbsp;&nbsp; 706882 |
| Shareholder servicing costs | &nbsp;&nbsp; 23101 |
| Administrative services fee | &nbsp;&nbsp; 141202 |
| Independent Trustees' compensation | &nbsp;&nbsp; 22842 |
| Custodian fee | &nbsp;&nbsp; 51732 |
| Shareholder communications | &nbsp;&nbsp; 66674 |
| Audit and tax fees | &nbsp;&nbsp; 36640 |
| Legal fees | &nbsp;&nbsp; 14401 |
| Miscellaneous | &nbsp;&nbsp; 24094 |
| Total expenses | &nbsp;&nbsp; $8299317 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (143612)<br>|
| Net expenses | &nbsp;&nbsp; $8155705 |
| Net investment income (loss) | &nbsp;&nbsp; $(2241711)<br>|
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $81663990 |
| Affiliated issuers | &nbsp;&nbsp; (4210)<br>|
| Foreign currency | &nbsp;&nbsp; 6270 |
| Net realized gain (loss)  | &nbsp;&nbsp; $81666050 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $71275258 |
| Affiliated issuers | &nbsp;&nbsp; (73)<br>|
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 20 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $71275205 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $152941255 |
| Change in net assets from operations | &nbsp;&nbsp; $150699544 |

---

**See Notes to Financial Statements**

------

MFS Growth Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $(2241711)<br>| &nbsp;&nbsp; $(5177131)<br>|
| Net realized gain (loss) | 81666050 | &nbsp;&nbsp; 399890478 |
| Net unrealized gain (loss) | 71275205 | &nbsp;&nbsp; 157006420 |
| Change in net assets from operations | $150699544 | &nbsp;&nbsp; $551719767 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(161162021)<br>|
| Change in net assets from fund share transactions | $(79937991)<br>| &nbsp;&nbsp; $(86101554)<br>|
| Total change in net assets | $70761553 | &nbsp;&nbsp; $304456192 |
| **Net assets** |  |  |
| At beginning of period | 2163241239 | &nbsp;&nbsp; 1858785047 |
| At end of period | $2234002792 | &nbsp;&nbsp; $2163241239 |

---

**See Notes to Financial Statements**

------

MFS Growth Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $73.31 | &nbsp;&nbsp; $60.29 | &nbsp;&nbsp; $48.02 | &nbsp;&nbsp; $79.36 | &nbsp;&nbsp; $73.81 | &nbsp;&nbsp; $59.40 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $(0.05)<br>| &nbsp;&nbsp; $(0.13)<br>| &nbsp;&nbsp; $(0.01)<br>| &nbsp;&nbsp; $(0.05)<br>| &nbsp;&nbsp; $(0.25)<br>| &nbsp;&nbsp; $(0.14)<br>|
| Net realized and unrealized gain (loss) | 5.28 | &nbsp;&nbsp;&nbsp;&nbsp;18.75 | &nbsp;&nbsp;&nbsp;&nbsp;16.76 | &nbsp;&nbsp; (24.26)<br>| &nbsp;&nbsp;&nbsp;&nbsp;17.21 | &nbsp;&nbsp;&nbsp;&nbsp;18.88 |
| Total from investment operations | $5.23 | &nbsp;&nbsp; $18.62 | &nbsp;&nbsp; $16.75 | &nbsp;&nbsp; $(24.31)<br>| &nbsp;&nbsp; $16.96 | &nbsp;&nbsp; $18.74 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | &nbsp;&nbsp; $(5.60)<br>| &nbsp;&nbsp; $(4.48)<br>| &nbsp;&nbsp; $(7.03)<br>| &nbsp;&nbsp; $(11.41)<br>| &nbsp;&nbsp; $(4.33)<br>|
| Net asset value, end of period (x) | $78.54 | &nbsp;&nbsp; $73.31 | &nbsp;&nbsp; $60.29 | &nbsp;&nbsp; $48.02 | &nbsp;&nbsp; $79.36 | &nbsp;&nbsp; $73.81 |
| Total return (%) (k)(r)(s)(x) | 7.13<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;31.47 | &nbsp;&nbsp;&nbsp;&nbsp;35.86 | &nbsp;&nbsp; (31.63)<br>| &nbsp;&nbsp;&nbsp;&nbsp;23.53 | &nbsp;&nbsp;&nbsp;&nbsp;31.86 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.74<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.73 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 | &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 |
| Expenses after expense reductions | 0.72<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.73 | &nbsp;&nbsp;&nbsp;&nbsp;0.73 | &nbsp;&nbsp;&nbsp;&nbsp;0.71 | &nbsp;&nbsp;&nbsp;&nbsp;0.72 |
| Net investment income (loss) | (0.15)(a)<br>| &nbsp;&nbsp; (0.19)<br>| &nbsp;&nbsp; (0.03)<br>| &nbsp;&nbsp; (0.09)<br>| &nbsp;&nbsp; (0.32)<br>| &nbsp;&nbsp; (0.21)<br>|
| Portfolio turnover rate | 19<br> (n)<br>| &nbsp;&nbsp; 33 | &nbsp;&nbsp; 23 | &nbsp;&nbsp; 18 | &nbsp;&nbsp; 12 | &nbsp;&nbsp; 29 |
| Net assets at end of period (000 omitted) | $1612654 | &nbsp;&nbsp; $1578587 | &nbsp;&nbsp; $1375609 | &nbsp;&nbsp; $1160108 | &nbsp;&nbsp; $1805385 | &nbsp;&nbsp; $1681327 |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $67.08 | &nbsp;&nbsp; $55.68 | &nbsp;&nbsp; $44.74 | &nbsp;&nbsp; $74.74 | &nbsp;&nbsp; $70.23 | &nbsp;&nbsp; $56.82 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $(0.13)<br>| &nbsp;&nbsp; $(0.28)<br>| &nbsp;&nbsp; $(0.14)<br>| &nbsp;&nbsp; $(0.18)<br>| &nbsp;&nbsp; $(0.42)<br>| &nbsp;&nbsp; $(0.29)<br>|
| Net realized and unrealized gain (loss) | 4.82 | &nbsp;&nbsp;&nbsp;&nbsp;17.28 | &nbsp;&nbsp;&nbsp;&nbsp;15.56 | &nbsp;&nbsp; (22.79)<br>| &nbsp;&nbsp;&nbsp;&nbsp;16.34 | &nbsp;&nbsp;&nbsp;&nbsp;18.03 |
| Total from investment operations | $4.69 | &nbsp;&nbsp; $17.00 | &nbsp;&nbsp; $15.42 | &nbsp;&nbsp; $(22.97)<br>| &nbsp;&nbsp; $15.92 | &nbsp;&nbsp; $17.74 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | &nbsp;&nbsp; $(5.60)<br>| &nbsp;&nbsp; $(4.48)<br>| &nbsp;&nbsp; $(7.03)<br>| &nbsp;&nbsp; $(11.41)<br>| &nbsp;&nbsp; $(4.33)<br>|
| Net asset value, end of period (x) | $71.77 | &nbsp;&nbsp; $67.08 | &nbsp;&nbsp; $55.68 | &nbsp;&nbsp; $44.74 | &nbsp;&nbsp; $74.74 | &nbsp;&nbsp; $70.23 |
| Total return (%) (k)(r)(s)(x) | 6.99<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;31.15 | &nbsp;&nbsp;&nbsp;&nbsp;35.51 | &nbsp;&nbsp; (31.80)<br>| &nbsp;&nbsp;&nbsp;&nbsp;23.24 | &nbsp;&nbsp;&nbsp;&nbsp;31.54 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.99<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.98 | &nbsp;&nbsp;&nbsp;&nbsp;0.99 | &nbsp;&nbsp;&nbsp;&nbsp;0.99 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.99 |
| Expenses after expense reductions | 0.97<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.98 | &nbsp;&nbsp;&nbsp;&nbsp;0.98 | &nbsp;&nbsp;&nbsp;&nbsp;0.96 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 |
| Net investment income (loss) | (0.40)(a)<br>| &nbsp;&nbsp; (0.43)<br>| &nbsp;&nbsp; (0.27)<br>| &nbsp;&nbsp; (0.34)<br>| &nbsp;&nbsp; (0.57)<br>| &nbsp;&nbsp; (0.46)<br>|
| Portfolio turnover rate | 19<br> (n)<br>| &nbsp;&nbsp; 33 | &nbsp;&nbsp; 23 | &nbsp;&nbsp; 18 | &nbsp;&nbsp; 12 | &nbsp;&nbsp; 29 |
| Net assets at end of period (000 omitted) | $621349 | &nbsp;&nbsp; $584655 | &nbsp;&nbsp; $483176 | &nbsp;&nbsp; $383804 | &nbsp;&nbsp; $574768 | &nbsp;&nbsp; $514102 |

---

**See Notes to Financial Statements**

------

MFS Growth Series

*Financial Highlights - continued*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Growth Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

During the reporting period, MFS Growth Series (the fund) was a diversified series of MFS Variable Insurance Trust (the trust). On June 18, 2025, pursuant to shareholder approval, the fund became a non-diversified series of the trust. The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by

------

MFS Growth Series

*Notes to Financial Statements (unaudited) - continued* 

events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $2229017092 | $— | $— | $2229017092 |
| Investment Companies | 9156638 |  |  | 9156638 |
| Total | $2238173730 | $— | $— | $2238173730 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend and interest payments received in additional securities are recorded on the ex-dividend or ex-interest date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for

------

MFS Growth Series

*Notes to Financial Statements (unaudited) - continued* 

all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to net operating losses and wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Long-term capital gains | &nbsp;&nbsp; $161162021 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $879484381 |
| Gross appreciation | &nbsp;&nbsp; 1366681322 |
| Gross depreciation | &nbsp;&nbsp; (7991973)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $1358689349 |
| <br>**As of 12/31/24** |  |
| Undistributed long-term capital gain | &nbsp;&nbsp; 399829748 |
| Other temporary differences | &nbsp;&nbsp; (19)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 1287598210 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $116812317 |
| Service Class |  | &nbsp;&nbsp; 44349704 |
| Total | $— | &nbsp;&nbsp; $161162021 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion | 0.65% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's

------

MFS Growth Series

*Notes to Financial Statements (unaudited) - continued* 

Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $143,612, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.68% of the fund's average daily net assets.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $21,384, which equated to 0.0021% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,717.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0137% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 3 shares of the Service Class for an amount of $221.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in purchase and sale transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $785,433 and $1,124,826, respectively. The sales transactions resulted in net realized gains (losses) of $(415,825).

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $17,341, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $399,327,016 and $479,355,338, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

------

MFS Growth Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 817362 | &nbsp;&nbsp; $56382648 | &nbsp;&nbsp; 1122502 | &nbsp;&nbsp; $78482654 |
| Service Class | 622635 | &nbsp;&nbsp; 40337648 | &nbsp;&nbsp; 1316511 | &nbsp;&nbsp; 84797164 |
|  | 1439997 | &nbsp;&nbsp; $96720296 | &nbsp;&nbsp; 2439013 | &nbsp;&nbsp; $163279818 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 1681294 | &nbsp;&nbsp; $116093354 |
| Service Class |  |  | &nbsp;&nbsp; 701292 | &nbsp;&nbsp; 44349704 |
|  |  | $— | &nbsp;&nbsp; 2382586 | &nbsp;&nbsp; $160443058 |
| Shares reacquired |  |  |  |  |
| Initial Class | (1816302)<br>| &nbsp;&nbsp; $(131382819)<br>| &nbsp;&nbsp; (4089048)<br>| &nbsp;&nbsp; $(287086285)<br>|
| Service Class | (681200)<br>| &nbsp;&nbsp; (45275468)<br>| &nbsp;&nbsp; (1979457)<br>| &nbsp;&nbsp; (122738145)<br>|
|  | (2497502)<br>| &nbsp;&nbsp; $(176658287)<br>| &nbsp;&nbsp; (6068505)<br>| &nbsp;&nbsp; $(409824430)<br>|
| Net change |  |  |  |  |
| Initial Class | (998940)<br>| &nbsp;&nbsp; $(75000171)<br>| &nbsp;&nbsp; (1285252)<br>| &nbsp;&nbsp; $(92510277)<br>|
| Service Class | (58565)<br>| &nbsp;&nbsp; (4937820)<br>| &nbsp;&nbsp; 38346 | &nbsp;&nbsp; 6408723 |
|  | (1057505)<br>| &nbsp;&nbsp; $(79937991)<br>| &nbsp;&nbsp; (1246906)<br>| &nbsp;&nbsp; $(86101554)<br>|

---

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio and the MFS Growth Allocation Portfolio were the owners of record of approximately 4% and 1%, respectively, of the value of outstanding voting shares of the fund. In addition, the MFS Conservative Allocation Portfolio was the owner of record of less than 1% of the value of outstanding voting shares of the fund.

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $5,109 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $11152490 | &nbsp;&nbsp; $165449537 | &nbsp;&nbsp; $167441106 | &nbsp;&nbsp; $(4210)<br>| &nbsp;&nbsp; $(73)<br>| &nbsp;&nbsp; $9156638 |

---

------

MFS Growth Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $510782 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Growth Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

At a special meeting of shareholders of MFS Growth Series, which was held on June 18, 2025, the following action was taken:

**Item 1:** To approve reclassifying the diversification status of the fund:

---

| | |
|:---|:---|
|  | **Number of Shares** |
| For | 1,298,779,725.960 |
| Against | 144,217,076.468 |
| Abstain | 72,441,658.004 |

---

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Growth Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Value Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Value Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 98.9% | Common Stocks – 98.9% | Common Stocks – 98.9% |
| Aerospace & Defense – 9.7% | Aerospace & Defense – 9.7% |  |
| Boeing Co. (a) | 297815 | &nbsp;&nbsp; $62401177 |
| General Dynamics Corp. | 170634 | &nbsp;&nbsp; 49767113 |
| Honeywell International, Inc. | 185248 | &nbsp;&nbsp; 43140554 |
| Northrop Grumman Corp. | 59660 | &nbsp;&nbsp; 29828807 |
| RTX Corp. | 437168 | &nbsp;&nbsp; 63835271 |
|  |  | &nbsp;&nbsp; $248972922 |
| Alcoholic Beverages – 0.3% | Alcoholic Beverages – 0.3% |  |
| Diageo PLC | 341535 | &nbsp;&nbsp; $8569809 |
| Brokerage & Asset Managers – 7.3% | Brokerage & Asset Managers – 7.3% |  |
| Blackrock, Inc. | 35456 | &nbsp;&nbsp; $37202208 |
| Citigroup, Inc. | 513703 | &nbsp;&nbsp; 43726399 |
| KKR & Co., Inc. | 356596 | &nbsp;&nbsp; 47437966 |
| LPL Financial Holdings, Inc. | 23883 | &nbsp;&nbsp; 8955409 |
| NASDAQ, Inc. | 563360 | &nbsp;&nbsp; 50375651 |
|  |  | &nbsp;&nbsp; $187697633 |
| Business Services – 2.8% | Business Services – 2.8% |  |
| Accenture PLC, "A" | 151034 | &nbsp;&nbsp; $45142552 |
| Equifax, Inc. | 100462 | &nbsp;&nbsp; 26056829 |
|  |  | &nbsp;&nbsp; $71199381 |
| Computer Software - Systems – 0.3% | Computer Software - Systems – 0.3% |  |
| CDW Corp. | 39127 | &nbsp;&nbsp; $6987691 |
| Construction – 1.3% | Construction – 1.3% |  |
| CRH PLC | 167768 | &nbsp;&nbsp; $15401102 |
| Otis Worldwide Corp. | 82633 | &nbsp;&nbsp; 8182320 |
| Sherwin-Williams Co. | 31101 | &nbsp;&nbsp; 10678839 |
|  |  | &nbsp;&nbsp; $34262261 |
| Consumer Products – 2.1% | Consumer Products – 2.1% |  |
| Kenvue, Inc. | 1046906 | &nbsp;&nbsp; $21911743 |
| Kimberly-Clark Corp. | 129093 | &nbsp;&nbsp; 16642670 |
| Reckitt Benckiser Group PLC | 227799 | &nbsp;&nbsp; 15493701 |
|  |  | &nbsp;&nbsp; $54048114 |
| Electrical Equipment – 0.4% | Electrical Equipment – 0.4% |  |
| W.W. Grainger, Inc. | 9148 | &nbsp;&nbsp; $9516116 |
| Electronics – 6.2% | Electronics – 6.2% |  |
| Analog Devices, Inc. | 214399 | &nbsp;&nbsp; $51031250 |
| KLA Corp. | 39300 | &nbsp;&nbsp; 35202582 |
| NXP Semiconductors N.V. | 154445 | &nbsp;&nbsp; 33744688 |
| Texas Instruments, Inc. | 186791 | &nbsp;&nbsp; 38781548 |
|  |  | &nbsp;&nbsp; $158760068 |

---

VLUFS-SEM

------

MFS Value Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Energy - Independent – 2.6% | Energy - Independent – 2.6% |  |
| ConocoPhillips | 514929 | &nbsp;&nbsp; $46209729 |
| EOG Resources, Inc. | 162974 | &nbsp;&nbsp; 19493320 |
|  |  | &nbsp;&nbsp; $65703049 |
| Energy - Integrated – 3.2% | Energy - Integrated – 3.2% |  |
| Chevron Corp. | 232258 | &nbsp;&nbsp; $33257023 |
| Exxon Mobil Corp. | 448373 | &nbsp;&nbsp; 48334609 |
|  |  | &nbsp;&nbsp; $81591632 |
| Food & Beverages – 3.3% | Food & Beverages – 3.3% |  |
| Mondelez International, Inc. | 414029 | &nbsp;&nbsp; $27922116 |
| Nestle S.A. | 297083 | &nbsp;&nbsp; 29515474 |
| PepsiCo, Inc. | 199260 | &nbsp;&nbsp; 26310290 |
|  |  | &nbsp;&nbsp; $83747880 |
| Gaming & Lodging – 1.3% | Gaming & Lodging – 1.3% |  |
| Marriott International, Inc., "A" | 126680 | &nbsp;&nbsp; $34610243 |
| Health Maintenance Organizations – 4.4% | Health Maintenance Organizations – 4.4% |  |
| Cigna Group | 253199 | &nbsp;&nbsp; $83702525 |
| Elevance Health, Inc. | 76405 | &nbsp;&nbsp; 29718489 |
|  |  | &nbsp;&nbsp; $113421014 |
| Insurance – 11.8% | Insurance – 11.8% |  |
| Aon PLC | 132101 | &nbsp;&nbsp; $47128353 |
| Chubb Ltd. | 152745 | &nbsp;&nbsp; 44253281 |
| Marsh & McLennan Cos., Inc. | 267098 | &nbsp;&nbsp; 58398307 |
| Progressive Corp. | 397039 | &nbsp;&nbsp; 105953827 |
| Travelers Cos., Inc. | 175413 | &nbsp;&nbsp; 46929994 |
|  |  | &nbsp;&nbsp; $302663762 |
| Machinery & Tools – 3.6% | Machinery & Tools – 3.6% |  |
| Eaton Corp. PLC | 80733 | &nbsp;&nbsp; $28820874 |
| Illinois Tool Works, Inc. | 110064 | &nbsp;&nbsp; 27213324 |
| PACCAR, Inc. | 296721 | &nbsp;&nbsp; 28206298 |
| Trane Technologies PLC | 18701 | &nbsp;&nbsp; 8180004 |
|  |  | &nbsp;&nbsp; $92420500 |
| Major Banks – 9.7% | Major Banks – 9.7% |  |
| JPMorgan Chase & Co. | 415759 | &nbsp;&nbsp; $120532692 |
| Morgan Stanley | 375427 | &nbsp;&nbsp; 52882647 |
| PNC Financial Services Group, Inc. | 231103 | &nbsp;&nbsp; 43082221 |
| Wells Fargo & Co. | 415100 | &nbsp;&nbsp; 33257812 |
|  |  | &nbsp;&nbsp; $249755372 |
| Medical & Health Technology & Services – 3.0% | Medical & Health Technology & Services – 3.0% |  |
| McKesson Corp. | 107078 | &nbsp;&nbsp; $78464617 |
| Medical Equipment – 1.5% | Medical Equipment – 1.5% |  |
| Abbott Laboratories | 283584 | &nbsp;&nbsp; $38570260 |
| Other Banks & Diversified Financials – 2.4% | Other Banks & Diversified Financials – 2.4% |  |
| American Express Co. | 195601 | &nbsp;&nbsp; $62392807 |

---

------

MFS Value Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Pharmaceuticals – 5.5% | Pharmaceuticals – 5.5% |  |
| AbbVie, Inc. | 193776 | &nbsp;&nbsp; $35968701 |
| Johnson & Johnson | 340023 | &nbsp;&nbsp; 51938513 |
| Merck & Co., Inc. | 239462 | &nbsp;&nbsp; 18955812 |
| Pfizer, Inc. | 1379575 | &nbsp;&nbsp; 33440898 |
|  |  | &nbsp;&nbsp; $140303924 |
| Railroad & Shipping – 2.1% | Railroad & Shipping – 2.1% |  |
| Canadian National Railway Co. | 104275 | &nbsp;&nbsp; $10848771 |
| Union Pacific Corp. | 192600 | &nbsp;&nbsp; 44313408 |
|  |  | &nbsp;&nbsp; $55162179 |
| Real Estate - Storage – 1.9% | Real Estate - Storage – 1.9% |  |
| Prologis, Inc., REIT | 387204 | &nbsp;&nbsp; $40702884 |
| Public Storage, Inc., REIT | 26887 | &nbsp;&nbsp; 7889184 |
|  |  | &nbsp;&nbsp; $48592068 |
| Specialty Chemicals – 0.7% | Specialty Chemicals – 0.7% |  |
| Corteva, Inc. | 121186 | &nbsp;&nbsp; $9031993 |
| DuPont de Nemours, Inc. | 146965 | &nbsp;&nbsp; 10080329 |
|  |  | &nbsp;&nbsp; $19112322 |
| Specialty Stores – 2.4% | Specialty Stores – 2.4% |  |
| Lowe's Cos., Inc. | 205250 | &nbsp;&nbsp; $45538818 |
| Target Corp. | 158156 | &nbsp;&nbsp; 15602089 |
|  |  | &nbsp;&nbsp; $61140907 |
| Utilities - Electric Power – 9.1% | Utilities - Electric Power – 9.1% |  |
| American Electric Power Co., Inc. | 108987 | &nbsp;&nbsp; $11308491 |
| Dominion Energy, Inc. | 793511 | &nbsp;&nbsp; 44849242 |
| Duke Energy Corp. | 440945 | &nbsp;&nbsp; 52031510 |
| Exelon Corp. | 446202 | &nbsp;&nbsp; 19374091 |
| PG&E Corp. | 1950273 | &nbsp;&nbsp; 27186805 |
| Southern Co. | 523658 | &nbsp;&nbsp; 48087514 |
| Xcel Energy, Inc. | 439607 | &nbsp;&nbsp; 29937237 |
|  |  | &nbsp;&nbsp; $232774890 |
| **Total Common Stocks (Identified Cost, $1,339,931,515)** |  | &nbsp;&nbsp; **$2540441421** |
| Mutual Funds (h) – 1.0% | Mutual Funds (h) – 1.0% | Mutual Funds (h) – 1.0% |
| Money Market Funds – 1.0% | Money Market Funds – 1.0% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $24,901,910) | 24901880 | &nbsp;&nbsp; $24904370 |
| Other Assets, Less Liabilities – 0.1% |  | &nbsp;&nbsp; 1700774 |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$2567046565** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $24,904,370 and $2,540,441,421, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

The following abbreviations are used in this report and are defined: <br> REIT Real Estate Investment Trust

**See Notes to Financial Statements**

------

MFS Value Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $1,339,931,515) | &nbsp;&nbsp; $2540441421 |
| Investments in affiliated issuers, at value (identified cost, $24,901,910) | &nbsp;&nbsp; 24904370 |
| Cash | &nbsp;&nbsp; 75942 |
| Receivables for |  |
| Fund shares sold | &nbsp;&nbsp; 1570026 |
| Dividends | &nbsp;&nbsp; 2223607 |
| Other assets | &nbsp;&nbsp; 2777 |
| Total assets | &nbsp;&nbsp; $2569218143 |
| **Liabilities** |  |
| Payables for |  |
| Fund shares reacquired | &nbsp;&nbsp; $1833395 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 153084 |
| Administrative services fee | &nbsp;&nbsp; 3647 |
| Shareholder servicing costs | &nbsp;&nbsp; 1026 |
| Distribution and/or service fees | &nbsp;&nbsp; 31776 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 8671 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 139979 |
| Total liabilities | &nbsp;&nbsp; $2171578 |
| Net assets | &nbsp;&nbsp; $2567046565 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $1041693486 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 1525353079 |
| Net assets | &nbsp;&nbsp; $2567046565 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 112744232 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $1397765139 | &nbsp;&nbsp;&nbsp; 60541886 | &nbsp;&nbsp;&nbsp; $23.09 |
| Service Class | &nbsp;&nbsp;&nbsp; 1169281426 | &nbsp;&nbsp;&nbsp; 52202346 | &nbsp;&nbsp;&nbsp;&nbsp;22.40 |

---

**See Notes to Financial Statements**

------

MFS Value Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $30807788 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 402042 |
| Other | &nbsp;&nbsp; 10229 |
| Foreign taxes withheld | &nbsp;&nbsp; (252764)<br>|
| Total investment income | &nbsp;&nbsp; $30967295 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $8597358 |
| Distribution and/or service fees | &nbsp;&nbsp; 1430903 |
| Shareholder servicing costs | &nbsp;&nbsp; 24300 |
| Administrative services fee | &nbsp;&nbsp; 169237 |
| Independent Trustees' compensation | &nbsp;&nbsp; 27327 |
| Custodian fee | &nbsp;&nbsp; 59019 |
| Shareholder communications | &nbsp;&nbsp; 30755 |
| Audit and tax fees | &nbsp;&nbsp; 36318 |
| Legal fees | &nbsp;&nbsp; 6623 |
| Miscellaneous | &nbsp;&nbsp; 26805 |
| Total expenses | &nbsp;&nbsp; $10408645 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (360702)<br>|
| Net expenses | &nbsp;&nbsp; $10047943 |
| Net investment income (loss) | &nbsp;&nbsp; $20919352 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $88807428 |
| Affiliated issuers | &nbsp;&nbsp; (1097)<br>|
| Foreign currency | &nbsp;&nbsp; 15458 |
| Net realized gain (loss)  | &nbsp;&nbsp; $88821789 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $54534852 |
| Affiliated issuers | &nbsp;&nbsp; 1282 |
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 82903 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $54619037 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $143440826 |
| Change in net assets from operations | &nbsp;&nbsp; $164360178 |

---

**See Notes to Financial Statements**

------

MFS Value Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $20919352 | &nbsp;&nbsp; $37797705 |
| Net realized gain (loss) | 88821789 | &nbsp;&nbsp; 187167952 |
| Net unrealized gain (loss) | 54619037 | &nbsp;&nbsp; 50366148 |
| Change in net assets from operations | $164360178 | &nbsp;&nbsp; $275331805 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(227399514)<br>|
| Change in net assets from fund share transactions | $(109808785)<br>| &nbsp;&nbsp; $10350105 |
| Total change in net assets | $54551393 | &nbsp;&nbsp; $58282396 |
| **Net assets** |  |  |
| At beginning of period | 2512495172 | &nbsp;&nbsp; 2454212776 |
| At end of period | $2567046565 | &nbsp;&nbsp; $2512495172 |

---

**See Notes to Financial Statements**

------

MFS Value Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $21.63 | &nbsp;&nbsp; $21.27 | &nbsp;&nbsp; $21.55 | &nbsp;&nbsp; $24.72 | &nbsp;&nbsp; $20.40 | &nbsp;&nbsp; $20.95 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.20 | &nbsp;&nbsp; $0.36 | &nbsp;&nbsp; $0.36 | &nbsp;&nbsp; $0.35 | &nbsp;&nbsp; $0.31 | &nbsp;&nbsp; $0.31 |
| Net realized and unrealized gain (loss) | 1.26 | &nbsp;&nbsp;&nbsp;&nbsp;2.12 | &nbsp;&nbsp;&nbsp;&nbsp;1.22 | &nbsp;&nbsp; (1.83)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.84 | &nbsp;&nbsp;&nbsp;&nbsp;0.29 |
| Total from investment operations | $1.46 | &nbsp;&nbsp; $2.48 | &nbsp;&nbsp; $1.58 | &nbsp;&nbsp; $(1.48)<br>| &nbsp;&nbsp; $5.15 | &nbsp;&nbsp; $0.60 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.38)<br>| &nbsp;&nbsp; $(0.36)<br>| &nbsp;&nbsp; $(0.32)<br>| &nbsp;&nbsp; $(0.31)<br>| &nbsp;&nbsp; $(0.30)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.74)<br>| &nbsp;&nbsp; (1.50)<br>| &nbsp;&nbsp; (1.37)<br>| &nbsp;&nbsp; (0.52)<br>| &nbsp;&nbsp; (0.85)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(2.12)<br>| &nbsp;&nbsp; $(1.86)<br>| &nbsp;&nbsp; $(1.69)<br>| &nbsp;&nbsp; $(0.83)<br>| &nbsp;&nbsp; $(1.15)<br>|
| Net asset value, end of period (x) | $23.09 | &nbsp;&nbsp; $21.63 | &nbsp;&nbsp; $21.27 | &nbsp;&nbsp; $21.55 | &nbsp;&nbsp; $24.72 | &nbsp;&nbsp; $20.40 |
| Total return (%) (k)(r)(s)(x) | 6.75<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;11.61 | &nbsp;&nbsp;&nbsp;&nbsp;7.93 | &nbsp;&nbsp; (5.91)<br>| &nbsp;&nbsp;&nbsp;&nbsp;25.45 | &nbsp;&nbsp;&nbsp;&nbsp;3.48 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.72<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.72 | &nbsp;&nbsp;&nbsp;&nbsp;0.73 |
| Expenses after expense reductions | 0.69<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.69 | &nbsp;&nbsp;&nbsp;&nbsp;0.69 | &nbsp;&nbsp;&nbsp;&nbsp;0.70 | &nbsp;&nbsp;&nbsp;&nbsp;0.70 | &nbsp;&nbsp;&nbsp;&nbsp;0.71 |
| Net investment income (loss) | 1.79<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.60 | &nbsp;&nbsp;&nbsp;&nbsp;1.73 | &nbsp;&nbsp;&nbsp;&nbsp;1.60 | &nbsp;&nbsp;&nbsp;&nbsp;1.33 | &nbsp;&nbsp;&nbsp;&nbsp;1.64 |
| Portfolio turnover rate | 6<br> (n)<br>| &nbsp;&nbsp; 15 | &nbsp;&nbsp; 16 | &nbsp;&nbsp; 13 | &nbsp;&nbsp; 9 | &nbsp;&nbsp; 17 |
| Net assets at end of period (000 omitted) | $1397765 | &nbsp;&nbsp; $1352605 | &nbsp;&nbsp; $1246269 | &nbsp;&nbsp; $1207158 | &nbsp;&nbsp; $1363583 | &nbsp;&nbsp; $1183318 |

---

**See Notes to Financial Statements**

------

MFS Value Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $21.01 | &nbsp;&nbsp; $20.72 | &nbsp;&nbsp; $21.03 | &nbsp;&nbsp; $24.16 | &nbsp;&nbsp; $19.96 | &nbsp;&nbsp; $20.52 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.16 | &nbsp;&nbsp; $0.29 | &nbsp;&nbsp; $0.30 | &nbsp;&nbsp; $0.29 | &nbsp;&nbsp; $0.24 | &nbsp;&nbsp; $0.25 |
| Net realized and unrealized gain (loss) | 1.23 | &nbsp;&nbsp;&nbsp;&nbsp;2.07 | &nbsp;&nbsp;&nbsp;&nbsp;1.19 | &nbsp;&nbsp; (1.79)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.75 | &nbsp;&nbsp;&nbsp;&nbsp;0.29 |
| Total from investment operations | $1.39 | &nbsp;&nbsp; $2.36 | &nbsp;&nbsp; $1.49 | &nbsp;&nbsp; $(1.50)<br>| &nbsp;&nbsp; $4.99 | &nbsp;&nbsp; $0.54 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.33)<br>| &nbsp;&nbsp; $(0.30)<br>| &nbsp;&nbsp; $(0.26)<br>| &nbsp;&nbsp; $(0.27)<br>| &nbsp;&nbsp; $(0.25)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.74)<br>| &nbsp;&nbsp; (1.50)<br>| &nbsp;&nbsp; (1.37)<br>| &nbsp;&nbsp; (0.52)<br>| &nbsp;&nbsp; (0.85)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(2.07)<br>| &nbsp;&nbsp; $(1.80)<br>| &nbsp;&nbsp; $(1.63)<br>| &nbsp;&nbsp; $(0.79)<br>| &nbsp;&nbsp; $(1.10)<br>|
| Net asset value, end of period (x) | $22.40 | &nbsp;&nbsp; $21.01 | &nbsp;&nbsp; $20.72 | &nbsp;&nbsp; $21.03 | &nbsp;&nbsp; $24.16 | &nbsp;&nbsp; $19.96 |
| Total return (%) (k)(r)(s)(x) | 6.62<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;11.30 | &nbsp;&nbsp;&nbsp;&nbsp;7.69 | &nbsp;&nbsp; (6.14)<br>| &nbsp;&nbsp;&nbsp;&nbsp;25.16 | &nbsp;&nbsp;&nbsp;&nbsp;3.22 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.97<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 | &nbsp;&nbsp;&nbsp;&nbsp;0.98 |
| Expenses after expense reductions | 0.94<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.94 | &nbsp;&nbsp;&nbsp;&nbsp;0.94 | &nbsp;&nbsp;&nbsp;&nbsp;0.95 | &nbsp;&nbsp;&nbsp;&nbsp;0.95 | &nbsp;&nbsp;&nbsp;&nbsp;0.96 |
| Net investment income (loss) | 1.54<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.35 | &nbsp;&nbsp;&nbsp;&nbsp;1.48 | &nbsp;&nbsp;&nbsp;&nbsp;1.35 | &nbsp;&nbsp;&nbsp;&nbsp;1.08 | &nbsp;&nbsp;&nbsp;&nbsp;1.38 |
| Portfolio turnover rate | 6<br> (n)<br>| &nbsp;&nbsp; 15 | &nbsp;&nbsp; 16 | &nbsp;&nbsp; 13 | &nbsp;&nbsp; 9 | &nbsp;&nbsp; 17 |
| Net assets at end of period (000 omitted) | $1169281 | &nbsp;&nbsp; $1159890 | &nbsp;&nbsp; $1207943 | &nbsp;&nbsp; $1239407 | &nbsp;&nbsp; $1469104 | &nbsp;&nbsp; $1267251 |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Value Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Value Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or

------

MFS Value Series

*Notes to Financial Statements (unaudited) - continued* 

market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $2540441421 | $— | $— | $2540441421 |
| Investment Companies | 24904370 |  |  | 24904370 |
| Total | $2565345791 | $— | $— | $2565345791 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign

------

MFS Value Series

*Notes to Financial Statements (unaudited) - continued* 

taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $39172482 |
| Long-term capital gains | &nbsp;&nbsp; 188227032 |
| Total distributions | &nbsp;&nbsp; $227399514 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $1375426004 |
| Gross appreciation | &nbsp;&nbsp; 1235649451 |
| Gross depreciation | &nbsp;&nbsp; (45729664)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $1189919787 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 41387154 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 185927356 |
| Other temporary differences | &nbsp;&nbsp; (3603)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 1133681994 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $118804687 |
| Service Class |  | &nbsp;&nbsp; 108594827 |
| Total | $— | &nbsp;&nbsp; $227399514 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion and up to $2.5 billion | 0.65% |
| In excess of $2.5 billion | 0.60% |

---

------

MFS Value Series

*Notes to Financial Statements (unaudited) - continued* 

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $173,500, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.68% of the fund's average daily net assets.

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses, such that total annual operating expenses do not exceed 0.69% of average daily net assets for the Initial Class shares and 0.94% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027. For the six months ended June 30, 2025, this reduction amounted to $187,202, which is included in the reduction of total expenses in the Statement of Operations.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $23,054, which equated to 0.0018% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,246.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0136% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 6 shares of Service Class for an aggregate amount of $127.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in purchase and sale transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $2,492,778 and $658,959, respectively. The sales transactions resulted in net realized gains (losses) of $489,386.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $9,915, which is included in "Other" income in the Statement of Operations.

------

MFS Value Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $139,724,011 and $243,577,460, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 2170099 | &nbsp;&nbsp; $47680715 | &nbsp;&nbsp; 11063345 | &nbsp;&nbsp; $243879336 |
| Service Class | 2330700 | &nbsp;&nbsp; 50079060 | &nbsp;&nbsp; 5256696 | &nbsp;&nbsp; 113945679 |
|  | 4500799 | &nbsp;&nbsp; $97759775 | &nbsp;&nbsp; 16320041 | &nbsp;&nbsp; $357825015 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 5469829 | &nbsp;&nbsp; $118804687 |
| Service Class |  |  | &nbsp;&nbsp; 5141801 | &nbsp;&nbsp; 108594827 |
|  |  | $— | &nbsp;&nbsp; 10611630 | &nbsp;&nbsp; $227399514 |
| Shares reacquired |  |  |  |  |
| Initial Class | (4168665)<br>| &nbsp;&nbsp; $(92377538)<br>| &nbsp;&nbsp; (12584842)<br>| &nbsp;&nbsp; $(281546545)<br>|
| Service Class | (5338585)<br>| &nbsp;&nbsp; (115191022)<br>| &nbsp;&nbsp; (13500589)<br>| &nbsp;&nbsp; (293327879)<br>|
|  | (9507250)<br>| &nbsp;&nbsp; $(207568560)<br>| &nbsp;&nbsp; (26085431)<br>| &nbsp;&nbsp; $(574874424)<br>|
| Net change |  |  |  |  |
| Initial Class | (1998566)<br>| &nbsp;&nbsp; $(44696823)<br>| &nbsp;&nbsp; 3948332 | &nbsp;&nbsp; $81137478 |
| Service Class | (3007885)<br>| &nbsp;&nbsp; (65111962)<br>| &nbsp;&nbsp; (3102092)<br>| &nbsp;&nbsp; (70787373)<br>|
|  | (5006451)<br>| &nbsp;&nbsp; $(109808785)<br>| &nbsp;&nbsp; 846240 | &nbsp;&nbsp; $10350105 |

---

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio and the MFS Growth Allocation Portfolio were the owners of record of approximately 3% and 1%, respectively, of the value of outstanding voting shares of the fund. In addition, the MFS Conservative Allocation Portfolio was the owner of record of less than 1% of the value of outstanding voting shares of the fund.

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $6,285 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

------

MFS Value Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $9567969 | &nbsp;&nbsp; $153561677 | &nbsp;&nbsp; $138225461 | &nbsp;&nbsp; $(1097)<br>| &nbsp;&nbsp; $1282 | &nbsp;&nbsp; $24904370 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $402042 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Value Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Value Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Value Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Research Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Research Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

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| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 99.3% | Common Stocks – 99.3% | Common Stocks – 99.3% |
| Aerospace & Defense – 2.9% | Aerospace & Defense – 2.9% |  |
| General Dynamics Corp. | 8477 | &nbsp;&nbsp; $2472402 |
| Howmet Aerospace, Inc. | 19173 | &nbsp;&nbsp; 3568671 |
| RTX Corp. | 34620 | &nbsp;&nbsp; 5055212 |
|  |  | &nbsp;&nbsp; $11096285 |
| Automotive – 0.5% | Automotive – 0.5% |  |
| Aptiv PLC (a) | 28442 | &nbsp;&nbsp; $1940313 |
| Broadcasting – 1.5% | Broadcasting – 1.5% |  |
| Omnicom Group, Inc. | 41937 | &nbsp;&nbsp; $3016948 |
| Spotify Technology S.A. (a) | 3714 | &nbsp;&nbsp; 2849901 |
|  |  | &nbsp;&nbsp; $5866849 |
| Brokerage & Asset Managers – 2.7% | Brokerage & Asset Managers – 2.7% |  |
| Charles Schwab Corp. | 42337 | &nbsp;&nbsp; $3862828 |
| CME Group, Inc. | 13881 | &nbsp;&nbsp; 3825881 |
| Evercore Partners, Inc. | 3560 | &nbsp;&nbsp; 961271 |
| KKR & Co., Inc. | 12508 | &nbsp;&nbsp; 1663940 |
|  |  | &nbsp;&nbsp; $10313920 |
| Business Services – 2.9% | Business Services – 2.9% |  |
| Accenture PLC, "A" | 12351 | &nbsp;&nbsp; $3691590 |
| Cognizant Technology Solutions Corp., "A" | 26105 | &nbsp;&nbsp; 2036973 |
| Fiserv, Inc. (a) | 14314 | &nbsp;&nbsp; 2467877 |
| TransUnion | 31707 | &nbsp;&nbsp; 2790216 |
|  |  | &nbsp;&nbsp; $10986656 |
| Computer Software – 14.4% | Computer Software – 14.4% |  |
| Atlassian Corp. (a) | 12521 | &nbsp;&nbsp; $2542890 |
| Cadence Design Systems, Inc. (a) | 11498 | &nbsp;&nbsp; 3543109 |
| Constellation Software, Inc. | 804 | &nbsp;&nbsp; 2948069 |
| Elastic N.V. (a) | 12854 | &nbsp;&nbsp; 1083978 |
| HubSpot, Inc. (a) | 3409 | &nbsp;&nbsp; 1897551 |
| Microsoft Corp. (s) | 65778 | &nbsp;&nbsp; 32718635 |
| Okta, Inc. (a) | 24232 | &nbsp;&nbsp; 2422473 |
| Salesforce, Inc. | 19190 | &nbsp;&nbsp; 5232921 |
| Tyler Technologies, Inc. (a) | 3808 | &nbsp;&nbsp; 2257535 |
|  |  | &nbsp;&nbsp; $54647161 |
| Computer Software - Systems – 5.1% | Computer Software - Systems – 5.1% |  |
| Apple, Inc. | 76649 | &nbsp;&nbsp; $15726075 |
| CDW Corp. | 9162 | &nbsp;&nbsp; 1636242 |
| EPAM Systems, Inc. (a) | 11789 | &nbsp;&nbsp; 2084531 |
|  |  | &nbsp;&nbsp; $19446848 |

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VFRFS-SEM

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MFS Research Series

*Portfolio of Investments (unaudited) – continued*

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| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Construction – 1.8% | Construction – 1.8% |  |
| CRH PLC | 30378 | &nbsp;&nbsp; $2788701 |
| Ferguson Enterprises, Inc. | 8427 | &nbsp;&nbsp; 1834979 |
| Sherwin-Williams Co. | 6051 | &nbsp;&nbsp; 2077671 |
|  |  | &nbsp;&nbsp; $6701351 |
| Consumer Products – 1.2% | Consumer Products – 1.2% |  |
| Colgate-Palmolive Co. | 22408 | &nbsp;&nbsp; $2036887 |
| Estée Lauder Cos., Inc., "A" | 12480 | &nbsp;&nbsp; 1008384 |
| Kenvue, Inc. | 77095 | &nbsp;&nbsp; 1613599 |
|  |  | &nbsp;&nbsp; $4658870 |
| Consumer Services – 1.0% | Consumer Services – 1.0% |  |
| Booking Holdings, Inc. | 386 | &nbsp;&nbsp; $2234646 |
| Expedia Group, Inc. | 10335 | &nbsp;&nbsp; 1743308 |
|  |  | &nbsp;&nbsp; $3977954 |
| Electrical Equipment – 1.6% | Electrical Equipment – 1.6% |  |
| Emerson Electric Co. | 28443 | &nbsp;&nbsp; $3792305 |
| TE Connectivity PLC | 12456 | &nbsp;&nbsp; 2100954 |
|  |  | &nbsp;&nbsp; $5893259 |
| Electronics – 10.1% | Electronics – 10.1% |  |
| Broadcom, Inc. | 34718 | &nbsp;&nbsp; $9570017 |
| Lam Research Corp. | 37254 | &nbsp;&nbsp; 3626304 |
| Marvell Technology, Inc. | 30497 | &nbsp;&nbsp; 2360468 |
| NVIDIA Corp. | 130480 | &nbsp;&nbsp; 20614535 |
| NXP Semiconductors N.V. | 9354 | &nbsp;&nbsp; 2043756 |
|  |  | &nbsp;&nbsp; $38215080 |
| Energy - Independent – 1.4% | Energy - Independent – 1.4% |  |
| ConocoPhillips | 34642 | &nbsp;&nbsp; $3108773 |
| Hess Corp. | 8517 | &nbsp;&nbsp; 1179945 |
| Valero Energy Corp. | 8859 | &nbsp;&nbsp; 1190827 |
|  |  | &nbsp;&nbsp; $5479545 |
| Energy - Integrated – 1.1% | Energy - Integrated – 1.1% |  |
| Exxon Mobil Corp. | 37729 | &nbsp;&nbsp; $4067186 |
| Food & Beverages – 1.5% | Food & Beverages – 1.5% |  |
| General Mills, Inc. | 22475 | &nbsp;&nbsp; $1164430 |
| Mondelez International, Inc. | 27238 | &nbsp;&nbsp; 1836931 |
| PepsiCo, Inc. | 21082 | &nbsp;&nbsp; 2783667 |
|  |  | &nbsp;&nbsp; $5785028 |
| Gaming & Lodging – 0.7% | Gaming & Lodging – 0.7% |  |
| Hilton Worldwide Holdings, Inc. | 10099 | &nbsp;&nbsp; $2689768 |
| General Merchandise – 0.5% | General Merchandise – 0.5% |  |
| Dollar General Corp. | 15415 | &nbsp;&nbsp; $1763168 |
| Health Maintenance Organizations – 1.3% | Health Maintenance Organizations – 1.3% |  |
| Cigna Group | 11163 | &nbsp;&nbsp; $3690265 |
| Humana, Inc. | 4977 | &nbsp;&nbsp; 1216777 |
|  |  | &nbsp;&nbsp; $4907042 |

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MFS Research Series

*Portfolio of Investments (unaudited) – continued*

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| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Insurance – 2.6% | Insurance – 2.6% |  |
| American International Group, Inc. | 19606 | &nbsp;&nbsp; $1678078 |
| Aon PLC | 8520 | &nbsp;&nbsp; 3039595 |
| Chubb Ltd. | 10717 | &nbsp;&nbsp; 3104929 |
| Willis Towers Watson PLC | 7060 | &nbsp;&nbsp; 2163890 |
|  |  | &nbsp;&nbsp; $9986492 |
| Interactive Media Services – 7.3% | Interactive Media Services – 7.3% |  |
| Alphabet, Inc., "A" (s) | 54929 | &nbsp;&nbsp; $9680138 |
| Meta Platforms, Inc., "A" | 24306 | &nbsp;&nbsp; 17940015 |
|  |  | &nbsp;&nbsp; $27620153 |
| Internet – 0.1% | Internet – 0.1% |  |
| Gartner, Inc. (a) | 1190 | &nbsp;&nbsp; $481022 |
| Machinery & Tools – 3.4% | Machinery & Tools – 3.4% |  |
| Eaton Corp. PLC | 10794 | &nbsp;&nbsp; $3853350 |
| Nordson Corp. | 11288 | &nbsp;&nbsp; 2419808 |
| Regal Rexnord Corp. | 13179 | &nbsp;&nbsp; 1910428 |
| Trane Technologies PLC | 6059 | &nbsp;&nbsp; 2650267 |
| Wabtec Corp. | 10465 | &nbsp;&nbsp; 2190848 |
|  |  | &nbsp;&nbsp; $13024701 |
| Major Banks – 4.4% | Major Banks – 4.4% |  |
| JPMorgan Chase & Co. | 33792 | &nbsp;&nbsp; $9796639 |
| Morgan Stanley | 23648 | &nbsp;&nbsp; 3331057 |
| PNC Financial Services Group, Inc. | 20047 | &nbsp;&nbsp; 3737162 |
|  |  | &nbsp;&nbsp; $16864858 |
| Medical & Health Technology & Services – 0.9% | Medical & Health Technology & Services – 0.9% |  |
| ICON PLC (a) | 5619 | &nbsp;&nbsp; $817284 |
| McKesson Corp. | 3448 | &nbsp;&nbsp; 2526625 |
|  |  | &nbsp;&nbsp; $3343909 |
| Medical Equipment – 4.2% | Medical Equipment – 4.2% |  |
| Agilent Technologies, Inc. | 17190 | &nbsp;&nbsp; $2028592 |
| Becton, Dickinson and Co. | 14265 | &nbsp;&nbsp; 2457146 |
| Boston Scientific Corp. (a) | 30673 | &nbsp;&nbsp; 3294587 |
| Medtronic PLC | 41076 | &nbsp;&nbsp; 3580595 |
| STERIS PLC | 10272 | &nbsp;&nbsp; 2467540 |
| Waters Corp. (a) | 5759 | &nbsp;&nbsp; 2010121 |
|  |  | &nbsp;&nbsp; $15838581 |
| Natural Gas - Pipeline – 0.3% | Natural Gas - Pipeline – 0.3% |  |
| Cheniere Energy, Inc. | 4472 | &nbsp;&nbsp; $1089021 |
| Oil Services – 0.2% | Oil Services – 0.2% |  |
| TechnipFMC PLC | 25683 | &nbsp;&nbsp; $884523 |
| Other Banks & Diversified Financials – 4.0% | Other Banks & Diversified Financials – 4.0% |  |
| Mastercard, Inc., "A" | 20161 | &nbsp;&nbsp; $11329272 |
| Moody's Corp. | 4166 | &nbsp;&nbsp; 2089624 |
| Northern Trust Corp. | 14562 | &nbsp;&nbsp; 1846316 |
|  |  | &nbsp;&nbsp; $15265212 |

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MFS Research Series

*Portfolio of Investments (unaudited) – continued*

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| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Pharmaceuticals – 3.6% | Pharmaceuticals – 3.6% |  |
| AbbVie, Inc. | 23431 | &nbsp;&nbsp; $4349262 |
| Johnson & Johnson | 30490 | &nbsp;&nbsp; 4657347 |
| Pfizer, Inc. | 93553 | &nbsp;&nbsp; 2267725 |
| Vertex Pharmaceuticals, Inc. (a) | 5165 | &nbsp;&nbsp; 2299458 |
|  |  | &nbsp;&nbsp; $13573792 |
| Railroad & Shipping – 0.5% | Railroad & Shipping – 0.5% |  |
| Union Pacific Corp. | 7616 | &nbsp;&nbsp; $1752289 |
| Real Estate - Storage – 0.5% | Real Estate - Storage – 0.5% |  |
| Extra Space Storage, Inc., REIT | 12704 | &nbsp;&nbsp; $1873078 |
| Restaurants – 2.0% | Restaurants – 2.0% |  |
| Aramark | 79710 | &nbsp;&nbsp; $3337457 |
| Starbucks Corp. | 17752 | &nbsp;&nbsp; 1626616 |
| U.S. Foods Holding Corp. (a) | 36282 | &nbsp;&nbsp; 2794077 |
|  |  | &nbsp;&nbsp; $7758150 |
| Specialty Chemicals – 1.2% | Specialty Chemicals – 1.2% |  |
| Air Products & Chemicals, Inc. | 8240 | &nbsp;&nbsp; $2324174 |
| Corteva, Inc. | 30562 | &nbsp;&nbsp; 2277786 |
|  |  | &nbsp;&nbsp; $4601960 |
| Specialty Stores – 7.0% | Specialty Stores – 7.0% |  |
| Amazon.com, Inc. (a)(s) | 83603 | &nbsp;&nbsp; $18341662 |
| BJ's Wholesale Club Holdings, Inc. (a) | 15831 | &nbsp;&nbsp; 1707057 |
| Home Depot, Inc. | 11300 | &nbsp;&nbsp; 4143032 |
| TJX Cos., Inc. | 18754 | &nbsp;&nbsp; 2315931 |
|  |  | &nbsp;&nbsp; $26507682 |
| Telecom - Infrastructure – 1.3% | Telecom - Infrastructure – 1.3% |  |
| American Tower Corp., REIT | 17184 | &nbsp;&nbsp; $3798007 |
| SBA Communications Corp., REIT | 4889 | &nbsp;&nbsp; 1148133 |
|  |  | &nbsp;&nbsp; $4946140 |
| Tobacco – 0.8% | Tobacco – 0.8% |  |
| Philip Morris International, Inc. | 15865 | &nbsp;&nbsp; $2889492 |
| Trucking – 0.4% | Trucking – 0.4% |  |
| J.B. Hunt Transport Services, Inc. | 10499 | &nbsp;&nbsp; $1507656 |
| Utilities - Electric Power – 2.4% | Utilities - Electric Power – 2.4% |  |
| Alliant Energy Corp. | 29682 | &nbsp;&nbsp; $1794870 |
| Duke Energy Corp. | 19482 | &nbsp;&nbsp; 2298876 |
| PG&E Corp. | 122421 | &nbsp;&nbsp; 1706549 |
| PPL Corp. | 49148 | &nbsp;&nbsp; 1665626 |
| Vistra Corp. | 7564 | &nbsp;&nbsp; 1465979 |
|  |  | &nbsp;&nbsp; $8931900 |
| **Total Common Stocks (Identified Cost, $221,455,028)** |  | &nbsp;&nbsp; **$377176894** |

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MFS Research Series

*Portfolio of Investments (unaudited) – continued*

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| | | | | |
|:---|:---|:---|:---|:---|
| **Issuer** | **Strike** <br>**Price**<br>| &nbsp;&nbsp; **First** <br>**Exercise**<br>| **Shares/Par** | **Value ($)** |
| Warrants – 0.0% |  |  |  |  |
| Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% | Computer Software – 0.0% |
| Constellation Software, Inc. (CAD 100 principal amount of Series 2 Debentures for 1 warrant, Expiration <br> 3/31/40) (a) (Identified Cost, $0)<br>| CAD 11.5 | N/A | 2981 | &nbsp;&nbsp; $0 |

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| | | |
|:---|:---|:---|
| Mutual Funds (h) – 0.8% | Mutual Funds (h) – 0.8% | Mutual Funds (h) – 0.8% |
| Money Market Funds – 0.8% | Money Market Funds – 0.8% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $3,252,426) | 3252210 | &nbsp;&nbsp; $3252536 |
| Other Assets, Less Liabilities – (0.1)% |  | &nbsp;&nbsp; (565211) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$379864219** |

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&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $3,252,536 and $377,176,894, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(s) Security or a portion of the security was pledged to cover collateral requirements.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

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| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| REIT | Real Estate Investment Trust |
| Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: | Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: |
| CAD | Canadian Dollar |

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At June 30, 2025, the fund had cash collateral of $5,168 and other liquid securities collateral with an aggregate value of $565,580. Restricted cash and/or deposits with brokers in the Statement of Assets and Liabilities are comprised of cash collateral.

**See Notes to Financial Statements**

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MFS Research Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

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| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $221,455,028) | &nbsp;&nbsp; $377176894 |
| Investments in affiliated issuers, at value (identified cost, $3,252,426) | &nbsp;&nbsp; 3252536 |
| Cash | &nbsp;&nbsp; 5493 |
| Deposits with brokers | &nbsp;&nbsp; 5168 |
| Receivables for |  |
| Fund shares sold | &nbsp;&nbsp; 12047 |
| Dividends | &nbsp;&nbsp; 232629 |
| Other assets | &nbsp;&nbsp; 959 |
| Total assets | &nbsp;&nbsp; $380685726 |
| **Liabilities** |  |
| Payables for |  |
| Fund shares reacquired | &nbsp;&nbsp; $731406 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 12879 |
| Administrative services fee | &nbsp;&nbsp; 645 |
| Shareholder servicing costs | &nbsp;&nbsp; 521 |
| Distribution and/or service fees | &nbsp;&nbsp; 2652 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 3030 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 70374 |
| Total liabilities | &nbsp;&nbsp; $821507 |
| Net assets | &nbsp;&nbsp; $379864219 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $(75407402)<br>|
| Total distributable earnings (loss) | &nbsp;&nbsp; 455271621 |
| Net assets | &nbsp;&nbsp; $379864219 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 10234281 |

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| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $282363903 | &nbsp;&nbsp;&nbsp; 7561548 | &nbsp;&nbsp;&nbsp; $37.34 |
| Service Class | &nbsp;&nbsp;&nbsp; 97500316 | &nbsp;&nbsp;&nbsp; 2672733 | &nbsp;&nbsp;&nbsp;&nbsp;36.48 |

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**See Notes to Financial Statements**

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MFS Research Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

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| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $2531644 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 125010 |
| Other | &nbsp;&nbsp; 6845 |
| Foreign taxes withheld | &nbsp;&nbsp; (3680)<br>|
| Total investment income | &nbsp;&nbsp; $2659819 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $1678280 |
| Distribution and/or service fees | &nbsp;&nbsp; 175978 |
| Shareholder servicing costs | &nbsp;&nbsp; 8062 |
| Administrative services fee | &nbsp;&nbsp; 35227 |
| Independent Trustees' compensation | &nbsp;&nbsp; 6298 |
| Custodian fee | &nbsp;&nbsp; 19496 |
| Shareholder communications | &nbsp;&nbsp; 19373 |
| Audit and tax fees | &nbsp;&nbsp; 36348 |
| Legal fees | &nbsp;&nbsp; 1964 |
| Miscellaneous | &nbsp;&nbsp; 17417 |
| Total expenses | &nbsp;&nbsp; $1998443 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (120477)<br>|
| Net expenses | &nbsp;&nbsp; $1877966 |
| Net investment income (loss) | &nbsp;&nbsp; $781853 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $211135021 |
| Affiliated issuers | &nbsp;&nbsp; (5946)<br>|
| Foreign currency | &nbsp;&nbsp; (1463)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $211127612 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $(180115702)<br>|
| Affiliated issuers | &nbsp;&nbsp; (372)<br>|
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 590 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $(180115484)<br>|
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $31012128 |
| Change in net assets from operations | &nbsp;&nbsp; $31793981 |

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**See Notes to Financial Statements**

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MFS Research Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

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| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $781853 | &nbsp;&nbsp; $2834772 |
| Net realized gain (loss) | 211127612 | &nbsp;&nbsp; 87809083 |
| Net unrealized gain (loss) | (180115484)<br>| &nbsp;&nbsp; 40103198 |
| Change in net assets from operations | $31793981 | &nbsp;&nbsp; $130747053 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(48420039)<br>|
| Change in net assets from fund share transactions | $(418980857)<br>| &nbsp;&nbsp; $(49393296)<br>|
| Total change in net assets | $(387186876)<br>| &nbsp;&nbsp; $32933718 |
| **Net assets** |  |  |
| At beginning of period | 767051095 | &nbsp;&nbsp; 734117377 |
| At end of period | $379864219 | &nbsp;&nbsp; $767051095 |

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**See Notes to Financial Statements**

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MFS Research Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $35.59 | &nbsp;&nbsp; $31.97 | &nbsp;&nbsp; $27.74 | &nbsp;&nbsp; $38.59 | &nbsp;&nbsp; $32.87 | &nbsp;&nbsp; $29.49 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.08 | &nbsp;&nbsp; $0.17 | &nbsp;&nbsp; $0.19 | &nbsp;&nbsp; $0.21 | &nbsp;&nbsp; $0.13 | &nbsp;&nbsp; $0.18 |
| Net realized and unrealized gain (loss) | 1.67 | &nbsp;&nbsp;&nbsp;&nbsp;5.76 | &nbsp;&nbsp;&nbsp;&nbsp;5.86 | &nbsp;&nbsp; (6.62)<br>| &nbsp;&nbsp;&nbsp;&nbsp;7.92 | &nbsp;&nbsp;&nbsp;&nbsp;4.62 |
| Total from investment operations | $1.75 | &nbsp;&nbsp; $5.93 | &nbsp;&nbsp; $6.05 | &nbsp;&nbsp; $(6.41)<br>| &nbsp;&nbsp; $8.05 | &nbsp;&nbsp; $4.80 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.22)<br>| &nbsp;&nbsp; $(0.16)<br>| &nbsp;&nbsp; $(0.16)<br>| &nbsp;&nbsp; $(0.20)<br>| &nbsp;&nbsp; $(0.22)<br>|
| From net realized gain |  | &nbsp;&nbsp; (2.09)<br>| &nbsp;&nbsp; (1.66)<br>| &nbsp;&nbsp; (4.28)<br>| &nbsp;&nbsp; (2.13)<br>| &nbsp;&nbsp; (1.20)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(2.31)<br>| &nbsp;&nbsp; $(1.82)<br>| &nbsp;&nbsp; $(4.44)<br>| &nbsp;&nbsp; $(2.33)<br>| &nbsp;&nbsp; $(1.42)<br>|
| Net asset value, end of period (x) | $37.34 | &nbsp;&nbsp; $35.59 | &nbsp;&nbsp; $31.97 | &nbsp;&nbsp; $27.74 | &nbsp;&nbsp; $38.59 | &nbsp;&nbsp; $32.87 |
| Total return (%) (k)(r)(s)(x) | 4.92<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;18.87 | &nbsp;&nbsp;&nbsp;&nbsp;22.42 | &nbsp;&nbsp; (17.21)<br>| &nbsp;&nbsp;&nbsp;&nbsp;24.80 | &nbsp;&nbsp;&nbsp;&nbsp;16.59 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.81<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.82 | &nbsp;&nbsp;&nbsp;&nbsp;0.82 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.82 |
| Expenses after expense reductions | 0.76<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 |
| Net investment income (loss) | 0.46<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.48 | &nbsp;&nbsp;&nbsp;&nbsp;0.64 | &nbsp;&nbsp;&nbsp;&nbsp;0.68 | &nbsp;&nbsp;&nbsp;&nbsp;0.35 | &nbsp;&nbsp;&nbsp;&nbsp;0.62 |
| Portfolio turnover rate | 22<br> (n)<br>| &nbsp;&nbsp; 22 | &nbsp;&nbsp; 22 | &nbsp;&nbsp; 24 | &nbsp;&nbsp; 19 | &nbsp;&nbsp; 39 |
| Net assets at end of period (000 omitted) | $282364 | &nbsp;&nbsp; $457306 | &nbsp;&nbsp; $423942 | &nbsp;&nbsp; $405178 | &nbsp;&nbsp; $384928 | &nbsp;&nbsp; $372405 |
| **Supplemental Ratios (%):** |  |  |  |  |  |  |
| Ratios of expenses to average net assets after expense reductions <br> excluding short sale expenses and interest expense and fees<br>| N/A | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 |

---

**See Notes to Financial Statements**

------

MFS Research Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $34.81 | &nbsp;&nbsp; $31.32 | &nbsp;&nbsp; $27.20 | &nbsp;&nbsp; $37.92 | &nbsp;&nbsp; $32.34 | &nbsp;&nbsp; $29.05 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.02 | &nbsp;&nbsp; $0.08 | &nbsp;&nbsp; $0.12 | &nbsp;&nbsp; $0.12 | &nbsp;&nbsp; $0.04 | &nbsp;&nbsp; $0.11 |
| Net realized and unrealized gain (loss) | 1.65 | &nbsp;&nbsp;&nbsp;&nbsp;5.63 | &nbsp;&nbsp;&nbsp;&nbsp;5.73 | &nbsp;&nbsp; (6.50)<br>| &nbsp;&nbsp;&nbsp;&nbsp;7.79 | &nbsp;&nbsp;&nbsp;&nbsp;4.54 |
| Total from investment operations | $1.67 | &nbsp;&nbsp; $5.71 | &nbsp;&nbsp; $5.85 | &nbsp;&nbsp; $(6.38)<br>| &nbsp;&nbsp; $7.83 | &nbsp;&nbsp; $4.65 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.13)<br>| &nbsp;&nbsp; $(0.07)<br>| &nbsp;&nbsp; $(0.06)<br>| &nbsp;&nbsp; $(0.12)<br>| &nbsp;&nbsp; $(0.16)<br>|
| From net realized gain |  | &nbsp;&nbsp; (2.09)<br>| &nbsp;&nbsp; (1.66)<br>| &nbsp;&nbsp; (4.28)<br>| &nbsp;&nbsp; (2.13)<br>| &nbsp;&nbsp; (1.20)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(2.22)<br>| &nbsp;&nbsp; $(1.73)<br>| &nbsp;&nbsp; $(4.34)<br>| &nbsp;&nbsp; $(2.25)<br>| &nbsp;&nbsp; $(1.36)<br>|
| Net asset value, end of period (x) | $36.48 | &nbsp;&nbsp; $34.81 | &nbsp;&nbsp; $31.32 | &nbsp;&nbsp; $27.20 | &nbsp;&nbsp; $37.92 | &nbsp;&nbsp; $32.34 |
| Total return (%) (k)(r)(s)(x) | 4.80<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;18.56 | &nbsp;&nbsp;&nbsp;&nbsp;22.12 | &nbsp;&nbsp; (17.43)<br>| &nbsp;&nbsp;&nbsp;&nbsp;24.51 | &nbsp;&nbsp;&nbsp;&nbsp;16.31 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.06<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.07 | &nbsp;&nbsp;&nbsp;&nbsp;1.07 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.07 |
| Expenses after expense reductions | 1.01<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 |
| Net investment income (loss) | 0.10<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.22 | &nbsp;&nbsp;&nbsp;&nbsp;0.40 | &nbsp;&nbsp;&nbsp;&nbsp;0.39 | &nbsp;&nbsp;&nbsp;&nbsp;0.10 | &nbsp;&nbsp;&nbsp;&nbsp;0.37 |
| Portfolio turnover rate | 22<br> (n)<br>| &nbsp;&nbsp; 22 | &nbsp;&nbsp; 22 | &nbsp;&nbsp; 24 | &nbsp;&nbsp; 19 | &nbsp;&nbsp; 39 |
| Net assets at end of period (000 omitted) | $97500 | &nbsp;&nbsp; $309746 | &nbsp;&nbsp; $310175 | &nbsp;&nbsp; $290421 | &nbsp;&nbsp; $396938 | &nbsp;&nbsp; $375322 |
| **Supplemental Ratios (%):** |  |  |  |  |  |  |
| Ratios of expenses to average net assets after expense reductions <br> excluding short sale expenses and interest expense and fees<br>| N/A | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Research Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Research Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities and equity securities sold short, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Equity securities sold short, for which there were no sales reported that day, are generally valued at the last quoted daily ask quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data.

------

MFS Research Series

*Notes to Financial Statements (unaudited) - continued* 

An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities: |  |  |  |  |
| United States | $371378924 | $— | $— | $371378924 |
| Canada | 2948069 | 0 |  | 2948069 |
| Sweden | 2849901 |  |  | 2849901 |
| Investment Companies | 3252536 |  |  | 3252536 |
| Total | $380429430 | $0 | $— | $380429430 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Short Sales** — The fund may enter into short sales whereby it sells a security it does not own in anticipation of a decline in the value of that security. The fund will realize a gain if the security price decreases and a loss if the security price increases between the date of the short sale and the date on which the fund replaces the borrowed security. Losses from short sales can exceed the proceeds of the security sold; and they can also exceed the potential loss from an ordinary buy and sell transaction. The amount of any premium, dividends, or interest the fund may be required to pay in connection with a short sale will be recognized as a fund expense. For the six months ended June 30, 2025, the fund did not enter into short sale transactions.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

------

MFS Research Series

*Notes to Financial Statements (unaudited) - continued* 

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $3885536 |
| Long-term capital gains | &nbsp;&nbsp; 44534503 |
| Total distributions | &nbsp;&nbsp; $48420039 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $227553883 |
| Gross appreciation | &nbsp;&nbsp; 160396418 |
| Gross depreciation | &nbsp;&nbsp; (7520871)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $152875547 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 9944759 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 80533576 |
| Other temporary differences | &nbsp;&nbsp; (590)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 332999895 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

------

MFS Research Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $28590596 |
| Service Class |  | &nbsp;&nbsp; 19829443 |
| Total | $— | &nbsp;&nbsp; $48420039 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion | 0.65% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $31,047, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.74% of the fund's average daily net assets.

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as short sale dividend and interest expenses incurred in connection with the fund's investment activity), such that total annual operating expenses do not exceed 0.76% of average daily net assets for the Initial Class shares and 1.01% of average daily net assets for the Service Class shares. This written agreement will terminate on July 31, 2025. For the six months ended June 30, 2025, this reduction amounted to $89,430, which is included in the reduction of total expenses in the Statement of Operations. Effective August 1, 2025, the investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses (such as short sale dividend and interest expenses incurred in connection with the fund's investment activity), such that total annual operating expenses do not exceed 0.74% of average daily net assets for the Initial Class shares and 0.99% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $7,043, which equated to 0.0031% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,019.

------

MFS Research Series

*Notes to Financial Statements (unaudited) - continued* 

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0157% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 4 shares of Service Class for an aggregate amount of $153.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $6,635, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $102,315,930 and $284,177,674, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 332895 | &nbsp;&nbsp; $10616973 | &nbsp;&nbsp; 624377 | &nbsp;&nbsp; $21767236 |
| Service Class | 178191 | &nbsp;&nbsp; 5966764 | &nbsp;&nbsp; 342690 | &nbsp;&nbsp; 11629854 |
|  | 511086 | &nbsp;&nbsp; $16583737 | &nbsp;&nbsp; 967067 | &nbsp;&nbsp; $33397090 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 839665 | &nbsp;&nbsp; $28590596 |
| Service Class |  |  | &nbsp;&nbsp; 594764 | &nbsp;&nbsp; 19829443 |
|  |  | $— | &nbsp;&nbsp; 1434429 | &nbsp;&nbsp; $48420039 |
| Shares reacquired |  |  |  |  |
| Initial Class | (5622260)<br>| &nbsp;&nbsp; $(206287714)<br>| &nbsp;&nbsp; (1871794)<br>| &nbsp;&nbsp; $(64806038)<br>|
| Service Class | (6403826)<br>| &nbsp;&nbsp; (229276880)<br>| &nbsp;&nbsp; (1941171)<br>| &nbsp;&nbsp; (66404387)<br>|
|  | (12026086)<br>| &nbsp;&nbsp; $(435564594)<br>| &nbsp;&nbsp; (3812965)<br>| &nbsp;&nbsp; $(131210425)<br>|
| Net change |  |  |  |  |
| Initial Class | (5289365)<br>| &nbsp;&nbsp; $(195670741)<br>| &nbsp;&nbsp; (407752)<br>| &nbsp;&nbsp; $(14448206)<br>|
| Service Class | (6225635)<br>| &nbsp;&nbsp; (223310116)<br>| &nbsp;&nbsp; (1003717)<br>| &nbsp;&nbsp; (34945090)<br>|
|  | (11515000)<br>| &nbsp;&nbsp; $(418980857)<br>| &nbsp;&nbsp; (1411469)<br>| &nbsp;&nbsp; $(49393296)<br>|

---

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio, the MFS Growth Allocation Portfolio, and the MFS Conservative Allocation Portfolio were the owners of record of approximately 18%, 8%, and 4%, respectively, of the value of outstanding voting shares of the fund.

------

MFS Research Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $1,408 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $5314544 | &nbsp;&nbsp; $164971583 | &nbsp;&nbsp; $167027273 | &nbsp;&nbsp; $(5946)<br>| &nbsp;&nbsp; $(372)<br>| &nbsp;&nbsp; $3252536 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $125010 | $— |

---

**(8) Redemptions In-Kind**

On February 7, 2025, the fund recorded a redemption in-kind of portfolio securities and cash that was valued at $234,254,866. The redeeming shareholder generally receives a pro rata share of the securities held by the fund. The distribution of such securities generated a realized gain of $116,265,298 for the fund, which is included in Net realized gain (loss) in the Statement of Operations. For tax purposes, no gains or losses were recognized with respect to the portfolio securities redeemed in-kind.

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Research Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Research Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Research Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS New Discovery Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS New Discovery Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 96.5% | Common Stocks – 96.5% | Common Stocks – 96.5% |
| Aerospace & Defense – 4.3% | Aerospace & Defense – 4.3% |  |
| CACI International, Inc., "A" (a) | 21601 | &nbsp;&nbsp; $10297197 |
| Karman Holdings, Inc. (a) | 88040 | &nbsp;&nbsp; 4434575 |
| KBR, Inc. | 103399 | &nbsp;&nbsp; 4956948 |
| Mirion Technologies, Inc. (a) | 250291 | &nbsp;&nbsp; 5388765 |
| Standard Aero, Inc. (a) | 176322 | &nbsp;&nbsp; 5580591 |
|  |  | &nbsp;&nbsp; $30658076 |
| Apparel Manufacturers – 0.7% | Apparel Manufacturers – 0.7% |  |
| Columbia Sportswear Co. | 86434 | &nbsp;&nbsp; $5279389 |
| Automotive – 3.4% | Automotive – 3.4% |  |
| ACV Auctions, Inc. (a) | 489069 | &nbsp;&nbsp; $7932699 |
| Modine Manufacturing Co. (a) | 64748 | &nbsp;&nbsp; 6377678 |
| Visteon Corp. (a) | 104971 | &nbsp;&nbsp; 9793795 |
|  |  | &nbsp;&nbsp; $24104172 |
| Biotechnology – 2.3% | Biotechnology – 2.3% |  |
| ABSCI Corp. (a)(l) | 507730 | &nbsp;&nbsp; $1304866 |
| Adaptive Biotechnologies Corp. (a) | 329544 | &nbsp;&nbsp; 3839188 |
| Blueprint Medicines Corp. (a) | 13985 | &nbsp;&nbsp; 1792597 |
| CG Oncology, Inc. (a) | 55280 | &nbsp;&nbsp; 1437280 |
| Exact Sciences Corp. (a) | 91761 | &nbsp;&nbsp; 4876179 |
| Immunocore Holdings PLC, ADR (a) | 100063 | &nbsp;&nbsp; 3139977 |
|  |  | &nbsp;&nbsp; $16390087 |
| Brokerage & Asset Managers – 5.3% | Brokerage & Asset Managers – 5.3% |  |
| GCM Grosvenor, Inc., "A" | 458334 | &nbsp;&nbsp; $5298341 |
| P10, Inc. | 455607 | &nbsp;&nbsp; 4656304 |
| PJT Partners, Inc. | 40471 | &nbsp;&nbsp; 6678120 |
| StepStone Group, Inc. | 218207 | &nbsp;&nbsp; 12110488 |
| WisdomTree Investments, Inc. | 804402 | &nbsp;&nbsp; 9258667 |
|  |  | &nbsp;&nbsp; $38001920 |
| Business Services – 1.9% | Business Services – 1.9% |  |
| ExlService Holdings, Inc. (a) | 162707 | &nbsp;&nbsp; $7124939 |
| TriNet Group, Inc. | 62562 | &nbsp;&nbsp; 4575785 |
| UL Solutions, Inc. | 24723 | &nbsp;&nbsp; 1801318 |
|  |  | &nbsp;&nbsp; $13502042 |
| Chemicals – 0.7% | Chemicals – 0.7% |  |
| BioLife Solutions, Inc. (a) | 245021 | &nbsp;&nbsp; $5277752 |
| Computer Software – 11.1% | Computer Software – 11.1% |  |
| Alkami Technology, Inc. (a) | 315962 | &nbsp;&nbsp; $9523095 |
| CCC Intelligent Holdings, Inc. (a) | 994819 | &nbsp;&nbsp; 9361247 |
| Elastic N.V. (a) | 73708 | &nbsp;&nbsp; 6215796 |
| Guidewire Software, Inc. (a) | 23610 | &nbsp;&nbsp; 5558974 |
| JFrog Ltd. (a) | 236809 | &nbsp;&nbsp; 10391179 |
| Kinaxis, Inc. (a) | 46100 | &nbsp;&nbsp; 6856010 |
| OneStream, Inc. (a) | 245533 | &nbsp;&nbsp; 6948584 |

---

VNDFS-SEM

------

MFS New Discovery Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Computer Software – continued | Computer Software – continued |  |
| Pegasystems, Inc. | 186980 | &nbsp;&nbsp; $10121227 |
| SentinelOne, Inc., "A" (a) | 344840 | &nbsp;&nbsp; 6303675 |
| ServiceTitan, Inc., "A" (a) | 28055 | &nbsp;&nbsp; 3006935 |
| VERTEX, Inc. (a) | 155923 | &nbsp;&nbsp; 5509539 |
|  |  | &nbsp;&nbsp; $79796261 |
| Computer Software - Systems – 1.3% | Computer Software - Systems – 1.3% |  |
| Q2 Holdings, Inc. (a) | 95826 | &nbsp;&nbsp; $8968355 |
| Construction – 5.6% | Construction – 5.6% |  |
| AZEK Co., Inc. (a) | 68818 | &nbsp;&nbsp; $3740258 |
| Independence Realty Trust, Inc., REIT | 447003 | &nbsp;&nbsp; 7907483 |
| James Hardie Industries PLC (a)(l) | 205964 | &nbsp;&nbsp; 5538372 |
| Knife River Corp. (a) | 135831 | &nbsp;&nbsp; 11089243 |
| QXO, Inc. (a) | 180604 | &nbsp;&nbsp; 3890210 |
| QXO, Inc. (PIPE) (a)(n) | 379925 | &nbsp;&nbsp; 8183585 |
|  |  | &nbsp;&nbsp; $40349151 |
| Consumer Products – 1.2% | Consumer Products – 1.2% |  |
| e.l.f. Beauty, Inc. (a) | 37308 | &nbsp;&nbsp; $4642608 |
| ODDITY Tech Ltd. (a) | 54500 | &nbsp;&nbsp; 4113115 |
|  |  | &nbsp;&nbsp; $8755723 |
| Containers – 1.0% | Containers – 1.0% |  |
| AptarGroup Inc. | 46198 | &nbsp;&nbsp; $7226753 |
| Electrical Equipment – 3.0% | Electrical Equipment – 3.0% |  |
| Littlefuse, Inc. | 30950 | &nbsp;&nbsp; $7017293 |
| nVent Electric PLC | 201539 | &nbsp;&nbsp; 14762732 |
|  |  | &nbsp;&nbsp; $21780025 |
| Electronics – 4.3% | Electronics – 4.3% |  |
| Advanced Energy Industries, Inc. | 82097 | &nbsp;&nbsp; $10877852 |
| Allegro MicroSystems, Inc. (a) | 119062 | &nbsp;&nbsp; 4070730 |
| Formfactor, Inc. (a) | 285786 | &nbsp;&nbsp; 9833896 |
| Onto Innovation, Inc. (a) | 58320 | &nbsp;&nbsp; 5886238 |
|  |  | &nbsp;&nbsp; $30668716 |
| Energy - Independent – 2.5% | Energy - Independent – 2.5% |  |
| Antero Resources Corp. (a) | 131030 | &nbsp;&nbsp; $5277888 |
| Matador Resources Co. | 91008 | &nbsp;&nbsp; 4342902 |
| Permian Resources Corp. | 302298 | &nbsp;&nbsp; 4117299 |
| Viper Energy, Inc. | 113062 | &nbsp;&nbsp; 4311054 |
|  |  | &nbsp;&nbsp; $18049143 |
| Energy - Renewables – 0.5% | Energy - Renewables – 0.5% |  |
| Bloom Energy Corp. (a) | 155477 | &nbsp;&nbsp; $3719010 |
| Engineering - Construction – 1.9% | Engineering - Construction – 1.9% |  |
| Jacobs Solutions, Inc. | 27501 | &nbsp;&nbsp; $3615007 |
| TopBuild Corp. (a) | 31796 | &nbsp;&nbsp; 10293637 |
|  |  | &nbsp;&nbsp; $13908644 |

---

------

MFS New Discovery Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Gaming & Lodging – 2.7% | Gaming & Lodging – 2.7% |  |
| Genius Sports Ltd. (a) | 1250102 | &nbsp;&nbsp; $13001061 |
| Sportradar Group AG (a) | 231506 | &nbsp;&nbsp; 6500688 |
|  |  | &nbsp;&nbsp; $19501749 |
| General Merchandise – 1.1% | General Merchandise – 1.1% |  |
| Ollie's Bargain Outlet Holdings, Inc. (a) | 57301 | &nbsp;&nbsp; $7551126 |
| Internet – 0.6% | Internet – 0.6% |  |
| Etoro Group Ltd. (a)(l) | 58232 | &nbsp;&nbsp; $3877669 |
| Leisure & Toys – 2.2% | Leisure & Toys – 2.2% |  |
| Brunswick Corp. | 94687 | &nbsp;&nbsp; $5230510 |
| Corsair Gaming, Inc. (a) | 463314 | &nbsp;&nbsp; 4369051 |
| Patrick Industries, Inc. | 65637 | &nbsp;&nbsp; 6056326 |
|  |  | &nbsp;&nbsp; $15655887 |
| Machinery & Tools – 5.7% | Machinery & Tools – 5.7% |  |
| Albany International Corp. | 61430 | &nbsp;&nbsp; $4308086 |
| Crane Co. | 65081 | &nbsp;&nbsp; 12358231 |
| Flowserve Corp. | 291939 | &nbsp;&nbsp; 15283007 |
| RB Global, Inc. | 84837 | &nbsp;&nbsp; 9008841 |
|  |  | &nbsp;&nbsp; $40958165 |
| Medical & Health Technology & Services – 3.8% | Medical & Health Technology & Services – 3.8% |  |
| Certara, Inc. (a) | 368766 | &nbsp;&nbsp; $4314562 |
| GeneDX Holdings Corp. (a) | 54442 | &nbsp;&nbsp; 5025541 |
| Guardant Health, Inc. (a) | 70667 | &nbsp;&nbsp; 3677511 |
| HealthEquity, Inc. (a) | 50084 | &nbsp;&nbsp; 5246800 |
| Schrodinger, Inc. (a) | 346609 | &nbsp;&nbsp; 6973773 |
| Tempus AI, Inc. (a)(l) | 31071 | &nbsp;&nbsp; 1974251 |
|  |  | &nbsp;&nbsp; $27212438 |
| Medical Equipment – 11.3% | Medical Equipment – 11.3% |  |
| Align Technology, Inc. (a) | 38144 | &nbsp;&nbsp; $7221803 |
| Bio-Techne Corp. | 192073 | &nbsp;&nbsp; 9882156 |
| Caris Life Sciences, Inc. (a) | 108330 | &nbsp;&nbsp; 2894578 |
| Ceribell, Inc. (a) | 127979 | &nbsp;&nbsp; 2397047 |
| Fractyl Health, Inc. (a) | 206861 | &nbsp;&nbsp; 335115 |
| Gerresheimer AG | 64074 | &nbsp;&nbsp; 3613791 |
| Globus Medical, Inc. (a) | 196059 | &nbsp;&nbsp; 11571402 |
| iRhythm Technologies, Inc. (a) | 29287 | &nbsp;&nbsp; 4509027 |
| Lantheus Holdings, Inc. (a) | 75932 | &nbsp;&nbsp; 6215793 |
| Masimo Corp. (a) | 30822 | &nbsp;&nbsp; 5184877 |
| Metsera, Inc. (a)(l) | 58679 | &nbsp;&nbsp; 1669418 |
| Outset Medical, Inc. (a)(l) | 147173 | &nbsp;&nbsp; 2827193 |
| PROCEPT BioRobotics Corp. (a) | 47292 | &nbsp;&nbsp; 2724019 |
| QIAGEN N.V. (a) | 222139 | &nbsp;&nbsp; 10676000 |
| UFP Technologies, Inc. (a) | 36316 | &nbsp;&nbsp; 8866915 |
|  |  | &nbsp;&nbsp; $80589134 |
| Oil Services – 0.9% | Oil Services – 0.9% |  |
| TechnipFMC PLC | 185305 | &nbsp;&nbsp; $6381904 |

---

------

MFS New Discovery Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Pharmaceuticals – 7.8% | Pharmaceuticals – 7.8% |  |
| Amicus Therapeutics, Inc. (a) | 832160 | &nbsp;&nbsp; $4768277 |
| Annexon, Inc. (a) | 228352 | &nbsp;&nbsp; 548045 |
| Ascendis Pharma, ADR (a) | 35862 | &nbsp;&nbsp; 6189781 |
| Collegium Pharmaceutical, Inc. (a) | 181483 | &nbsp;&nbsp; 5366452 |
| Cytokinetics, Inc. (a) | 107108 | &nbsp;&nbsp; 3538848 |
| Harmony Biosciences Holdings (a) | 148413 | &nbsp;&nbsp; 4689851 |
| Ionis Pharmaceuticals, Inc. (a) | 119834 | &nbsp;&nbsp; 4734641 |
| Kymera Therapeutics, Inc. (a) | 104129 | &nbsp;&nbsp; 4544190 |
| Legend Biotech Corp., ADR (a) | 103074 | &nbsp;&nbsp; 3658096 |
| Ligand Pharmaceuticals, Inc. (a) | 78588 | &nbsp;&nbsp; 8933884 |
| Neurocrine Biosciences, Inc. (a) | 39588 | &nbsp;&nbsp; 4975816 |
| Ultragenyx Pharmaceutical, Inc. (a) | 104426 | &nbsp;&nbsp; 3796929 |
|  |  | &nbsp;&nbsp; $55744810 |
| Pollution Control – 0.9% | Pollution Control – 0.9% |  |
| GFL Environmental, Inc. | 120464 | &nbsp;&nbsp; $6078613 |
| Real Estate – 0.7% | Real Estate – 0.7% |  |
| DigitalBridge Group, Inc., REIT | 499176 | &nbsp;&nbsp; $5166472 |
| Real Estate - Storage – 2.0% | Real Estate - Storage – 2.0% |  |
| STAG Industrial, Inc., REIT | 137549 | &nbsp;&nbsp; $4990278 |
| Terreno Realty Corp., REIT | 167849 | &nbsp;&nbsp; 9411293 |
|  |  | &nbsp;&nbsp; $14401571 |
| Restaurants – 3.8% | Restaurants – 3.8% |  |
| Chefs' Warehouse, Inc. (a) | 111888 | &nbsp;&nbsp; $7139573 |
| U.S. Foods Holding Corp. (a) | 152988 | &nbsp;&nbsp; 11781606 |
| Wingstop, Inc. | 25011 | &nbsp;&nbsp; 8422204 |
|  |  | &nbsp;&nbsp; $27343383 |
| Specialty Chemicals – 0.3% | Specialty Chemicals – 0.3% |  |
| Axalta Coating Systems Ltd. (a) | 76898 | &nbsp;&nbsp; $2283102 |
| Trucking – 1.7% | Trucking – 1.7% |  |
| Knight-Swift Transportation Holdings, Inc. | 139705 | &nbsp;&nbsp; $6179152 |
| XPO, Inc. (a) | 49349 | &nbsp;&nbsp; 6232285 |
|  |  | &nbsp;&nbsp; $12411437 |
| **Total Common Stocks (Identified Cost, $573,734,426)** |  | &nbsp;&nbsp; **$691592679** |
| Mutual Funds (h) – 3.8% | Mutual Funds (h) – 3.8% | Mutual Funds (h) – 3.8% |
| Money Market Funds – 3.8% | Money Market Funds – 3.8% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $27,194,071) | 27194114 | &nbsp;&nbsp; $27196833 |
| Collateral for Securities Loaned – 2.2% | Collateral for Securities Loaned – 2.2% | Collateral for Securities Loaned – 2.2% |
| JPMorgan U.S. Government Money Market Fund - Class IM Shares, 4.26% (j) (Identified Cost, $15,973,000) | 15973000 | &nbsp;&nbsp; $15973000 |
| Other Assets, Less Liabilities – (2.5)% |  | &nbsp;&nbsp; (18169668) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$716592844** |

---

------

MFS New Discovery Series

*Portfolio of Investments (unaudited) – continued*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $27,196,833 and $707,565,679, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(j) The rate quoted is the annualized seven-day yield of the fund at period end.

&nbsp;&nbsp;&nbsp;&nbsp;(l) A portion of this security is on loan. See Note 2 for additional information.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933.
 These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers.
 At period end, the aggregate value of these securities was $8,183,585, representing 1.1% of net assets.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

---

| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| ADR | American Depositary Receipt |
| PIPE | Private Investment in Public Equity |
| REIT | Real Estate Investment Trust |

---

**See Notes to Financial Statements**

------

MFS New Discovery Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value, including $15,464,596 of securities on loan (identified cost, $589,707,426) | &nbsp;&nbsp; $707565679 |
| Investments in affiliated issuers, at value (identified cost, $27,194,071) | &nbsp;&nbsp; 27196833 |
| Receivables for |  |
| Investments sold | &nbsp;&nbsp; 3667401 |
| Fund shares sold | &nbsp;&nbsp; 61986 |
| Interest and dividends | &nbsp;&nbsp; 459965 |
| Other assets | &nbsp;&nbsp; 3811 |
| Total assets | &nbsp;&nbsp; $738955675 |
| **Liabilities** |  |
| Payable to custodian | &nbsp;&nbsp; $2317 |
| Payables for |  |
| Investments purchased | &nbsp;&nbsp; 5524781 |
| Fund shares reacquired | &nbsp;&nbsp; 691671 |
| Collateral for securities loaned, at value | &nbsp;&nbsp; 15973000 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 29476 |
| Administrative services fee | &nbsp;&nbsp; 1114 |
| Shareholder servicing costs | &nbsp;&nbsp; 867 |
| Distribution and/or service fees | &nbsp;&nbsp; 11511 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 2692 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 125402 |
| Total liabilities | &nbsp;&nbsp; $22362831 |
| Net assets | &nbsp;&nbsp; $716592844 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $725544709 |
| Total distributable earnings (loss) | &nbsp;&nbsp; (8951865)<br>|
| Net assets | &nbsp;&nbsp; $716592844 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 58289898 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $295832176 | &nbsp;&nbsp;&nbsp; 20596505 | &nbsp;&nbsp;&nbsp; $14.36 |
| Service Class | &nbsp;&nbsp;&nbsp; 420760668 | &nbsp;&nbsp;&nbsp; 37693393 | &nbsp;&nbsp;&nbsp;&nbsp;11.16 |

---

**See Notes to Financial Statements**

------

MFS New Discovery Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $2170520 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 689672 |
| Income on securities loaned | &nbsp;&nbsp; 138935 |
| Other | &nbsp;&nbsp; 37912 |
| Foreign taxes withheld | &nbsp;&nbsp; (10304)<br>|
| Total investment income | &nbsp;&nbsp; $3026735 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $3069022 |
| Distribution and/or service fees | &nbsp;&nbsp; 497973 |
| Shareholder servicing costs | &nbsp;&nbsp; 15868 |
| Administrative services fee | &nbsp;&nbsp; 50279 |
| Independent Trustees' compensation | &nbsp;&nbsp; 8169 |
| Custodian fee | &nbsp;&nbsp; 17731 |
| Shareholder communications | &nbsp;&nbsp; 18301 |
| Audit and tax fees | &nbsp;&nbsp; 34296 |
| Legal fees | &nbsp;&nbsp; 1839 |
| Miscellaneous | &nbsp;&nbsp; 18270 |
| Total expenses | &nbsp;&nbsp; $3731748 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (262863)<br>|
| Net expenses | &nbsp;&nbsp; $3468885 |
| Net investment income (loss) | &nbsp;&nbsp; $(442150)<br>|
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $1081628 |
| Affiliated issuers | &nbsp;&nbsp; (2156)<br>|
| Foreign currency | &nbsp;&nbsp; (1844)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $1077628 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $27700522 |
| Affiliated issuers | &nbsp;&nbsp; (2292)<br>|
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 18684 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $27716914 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $28794542 |
| Change in net assets from operations | &nbsp;&nbsp; $28352392 |

---

**See Notes to Financial Statements**

------

MFS New Discovery Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $(442150)<br>| &nbsp;&nbsp; $(1634268)<br>|
| Net realized gain (loss) | 1077628 | &nbsp;&nbsp; 29975917 |
| Net unrealized gain (loss) | 27716914 | &nbsp;&nbsp; 16292304 |
| Change in net assets from operations | $28352392 | &nbsp;&nbsp; $44633953 |
| Change in net assets from fund share transactions | $(25278132)<br>| &nbsp;&nbsp; $(46304789)<br>|
| Total change in net assets | $3074260 | &nbsp;&nbsp; $(1670836)<br>|
| **Net assets** |  |  |
| At beginning of period | 713518584 | &nbsp;&nbsp; 715189420 |
| At end of period | $716592844 | &nbsp;&nbsp; $713518584 |

---

**See Notes to Financial Statements**

------

MFS New Discovery Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $13.81 | &nbsp;&nbsp; $12.94 | &nbsp;&nbsp; $11.31 | &nbsp;&nbsp; $23.30 | &nbsp;&nbsp; $26.96 | &nbsp;&nbsp; $20.28 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.00<br> (w)<br>| &nbsp;&nbsp; $(0.01)<br>| &nbsp;&nbsp; $(0.02)<br>| &nbsp;&nbsp; $(0.04)<br>| &nbsp;&nbsp; $(0.11)<br>| &nbsp;&nbsp; $(0.06)<br>|
| Net realized and unrealized gain (loss) | 0.55 | &nbsp;&nbsp;&nbsp;&nbsp;0.88 | &nbsp;&nbsp;&nbsp;&nbsp;1.65 | &nbsp;&nbsp; (6.56)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.92 | &nbsp;&nbsp;&nbsp;&nbsp;8.84 |
| Total from investment operations | $0.55 | &nbsp;&nbsp; $0.87 | &nbsp;&nbsp; $1.63 | &nbsp;&nbsp; $(6.60)<br>| &nbsp;&nbsp; $0.81 | &nbsp;&nbsp; $8.78 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | $— | $— | &nbsp;&nbsp; $(5.39)<br>| &nbsp;&nbsp; $(4.47)<br>| &nbsp;&nbsp; $(2.10)<br>|
| Net asset value, end of period (x) | $14.36 | &nbsp;&nbsp; $13.81 | &nbsp;&nbsp; $12.94 | &nbsp;&nbsp; $11.31 | &nbsp;&nbsp; $23.30 | &nbsp;&nbsp; $26.96 |
| Total return (%) (k)(r)(s)(x) | 3.98<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;6.72 | &nbsp;&nbsp;&nbsp;&nbsp;14.41 | &nbsp;&nbsp; (29.76)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.80 | &nbsp;&nbsp;&nbsp;&nbsp;45.89 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.95<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.95 | &nbsp;&nbsp;&nbsp;&nbsp;0.94 | &nbsp;&nbsp;&nbsp;&nbsp;0.95 | &nbsp;&nbsp;&nbsp;&nbsp;0.94 | &nbsp;&nbsp;&nbsp;&nbsp;0.95 |
| Expenses after expense reductions | 0.87<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.87 | &nbsp;&nbsp;&nbsp;&nbsp;0.87 | &nbsp;&nbsp;&nbsp;&nbsp;0.87 | &nbsp;&nbsp;&nbsp;&nbsp;0.87 | &nbsp;&nbsp;&nbsp;&nbsp;0.91 |
| Net investment income (loss) | 0.02<br> (a)<br>| &nbsp;&nbsp; (0.08)<br>| &nbsp;&nbsp; (0.14)<br>| &nbsp;&nbsp; (0.23)<br>| &nbsp;&nbsp; (0.42)<br>| &nbsp;&nbsp; (0.30)<br>|
| Portfolio turnover rate | 42<br> (n)<br>| &nbsp;&nbsp; 66 | &nbsp;&nbsp; 61 | &nbsp;&nbsp; 48 | &nbsp;&nbsp; 79 | &nbsp;&nbsp; 80 |
| Net assets at end of period (000 omitted) | $295832 | &nbsp;&nbsp; $294444 | &nbsp;&nbsp; $308484 | &nbsp;&nbsp; $286747 | &nbsp;&nbsp; $433168 | &nbsp;&nbsp; $465663 |

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $10.75 | &nbsp;&nbsp; $10.10 | &nbsp;&nbsp; $8.84 | &nbsp;&nbsp; $19.84 | &nbsp;&nbsp; $23.61 | &nbsp;&nbsp; $18.02 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $(0.01)<br>| &nbsp;&nbsp; $(0.04)<br>| &nbsp;&nbsp; $(0.04)<br>| &nbsp;&nbsp; $(0.06)<br>| &nbsp;&nbsp; $(0.16)<br>| &nbsp;&nbsp; $(0.10)<br>|
| Net realized and unrealized gain (loss) | 0.42 | &nbsp;&nbsp;&nbsp;&nbsp;0.69 | &nbsp;&nbsp;&nbsp;&nbsp;1.30 | &nbsp;&nbsp; (5.55)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.86 | &nbsp;&nbsp;&nbsp;&nbsp;7.79 |
| Total from investment operations | $0.41 | &nbsp;&nbsp; $0.65 | &nbsp;&nbsp; $1.26 | &nbsp;&nbsp; $(5.61)<br>| &nbsp;&nbsp; $0.70 | &nbsp;&nbsp; $7.69 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net realized gain | $— | $— | $— | &nbsp;&nbsp; $(5.39)<br>| &nbsp;&nbsp; $(4.47)<br>| &nbsp;&nbsp; $(2.10)<br>|
| Net asset value, end of period (x) | $11.16 | &nbsp;&nbsp; $10.75 | &nbsp;&nbsp; $10.10 | &nbsp;&nbsp; $8.84 | &nbsp;&nbsp; $19.84 | &nbsp;&nbsp; $23.61 |
| Total return (%) (k)(r)(s)(x) | 3.81<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;6.44 | &nbsp;&nbsp;&nbsp;&nbsp;14.25 | &nbsp;&nbsp; (29.99)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.57 | &nbsp;&nbsp;&nbsp;&nbsp;45.58 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.20<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.20 | &nbsp;&nbsp;&nbsp;&nbsp;1.19 | &nbsp;&nbsp;&nbsp;&nbsp;1.20 | &nbsp;&nbsp;&nbsp;&nbsp;1.19 | &nbsp;&nbsp;&nbsp;&nbsp;1.20 |
| Expenses after expense reductions | 1.12<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.12 | &nbsp;&nbsp;&nbsp;&nbsp;1.12 | &nbsp;&nbsp;&nbsp;&nbsp;1.12 | &nbsp;&nbsp;&nbsp;&nbsp;1.12 | &nbsp;&nbsp;&nbsp;&nbsp;1.16 |
| Net investment income (loss) | (0.23)(a)<br>| &nbsp;&nbsp; (0.33)<br>| &nbsp;&nbsp; (0.39)<br>| &nbsp;&nbsp; (0.48)<br>| &nbsp;&nbsp; (0.66)<br>| &nbsp;&nbsp; (0.56)<br>|
| Portfolio turnover rate | 42<br> (n)<br>| &nbsp;&nbsp; 66 | &nbsp;&nbsp; 61 | &nbsp;&nbsp; 48 | &nbsp;&nbsp; 79 | &nbsp;&nbsp; 80 |
| Net assets at end of period (000 omitted) | $420761 | &nbsp;&nbsp; $419075 | &nbsp;&nbsp; $406706 | &nbsp;&nbsp; $374602 | &nbsp;&nbsp; $572116 | &nbsp;&nbsp; $584928 |

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**See Notes to Financial Statements**

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MFS New Discovery Series

*Financial Highlights - continued*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(w) Per share amount was less than $0.01.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

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MFS New Discovery Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS New Discovery Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued. The fund will generally focus on securities of small size companies which may be more volatile than those of larger companies. The fund invests in foreign securities. Investments in foreign securities are vulnerable to the effects of changes in the relative values of the local currency and the U.S. dollar and to the effects of changes in each country's market, economic, industrial, political, regulatory, geopolitical, environmental, public health, and other conditions.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be

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MFS New Discovery Series

*Notes to Financial Statements (unaudited) - continued* 

valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

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| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities: |  |  |  |  |
| United States | $601157080 | $8183585 | $— | $609340665 |
| Canada | 21943464 |  |  | 21943464 |
| United Kingdom | 16141038 |  |  | 16141038 |
| Germany | 14289791 |  |  | 14289791 |
| Israel | 7990784 |  |  | 7990784 |
| Switzerland | 6500688 |  |  | 6500688 |
| Denmark | 6189781 |  |  | 6189781 |
| Australia | 5538372 |  |  | 5538372 |
| China | 3658096 |  |  | 3658096 |
| Investment Companies | 43169833 |  |  | 43169833 |
| Total | $726578927 | $8183585 | $— | $734762512 |

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For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Security Loans** — Under its Securities Lending Agency Agreement with the fund, Goldman Sachs Agency Lending, as lending agent, loans the securities of the fund to certain qualified institutions (the "Borrowers") approved by the fund. Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returned within the earlier of the standard trade settlement period for such securities or within five business days. The loans are collateralized by cash and/or U.S. government securities in an amount typically at least equal to the market value of the securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of the loaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund on the next business day. The lending agent provides the fund with indemnification against Borrower default. In the event of Borrower default, the lending agent will, for the benefit of the fund, either purchase securities identical to those loaned or pay the fund the market value of the loaned securities. In

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MFS New Discovery Series

*Notes to Financial Statements (unaudited) - continued* 

return, the lending agent assumes the fund's rights to the related collateral. If the collateral value is less than the cost to purchase identical securities or the cash needed to pay their market value, the lending agent is responsible for the shortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment for which the fund bears the risk of loss. At period end, the fund had investment securities on loan, all of which were classified as equity securities in the fund's Portfolio of Investments, with a fair value of $15,464,596. The fair value of the fund's investment securities on loan and a related liability of $15,973,000 for the obligation to return cash collateral received on securities loaned are both presented gross in the Statement of Assets and Liabilities. The collateral on securities loaned exceeded the value of securities on loan at period end. The liability for cash collateral for securities loaned is carried at fair value, which is categorized as level 2 within the fair value hierarchy. A portion of the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated between the fund and the lending agent. On loans collateralized by U.S. government securities, a fee is received from the Borrower, and is allocated between the fund and the lending agent. Income from securities lending is separately reported in the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the same manner as other dividend and interest income.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to net operating losses, passive foreign investment companies, and wash sale loss deferrals.

The fund declared no distributions for the current period or for the year ended December 31, 2024.

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MFS New Discovery Series

*Notes to Financial Statements (unaudited) - continued* 

The federal tax cost and the tax basis components of distributable earnings were as follows:

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| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $629320573 |
| Gross appreciation | &nbsp;&nbsp; 144409483 |
| Gross depreciation | &nbsp;&nbsp; (38967544)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $105441939 |
| <br>**As of 12/31/24** |  |
| Capital loss carryforwards | &nbsp;&nbsp; (115037672)<br>|
| Other temporary differences | &nbsp;&nbsp; (10294)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 77743709 |

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The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

As of December 31, 2024, the fund had capital loss carryforwards available to offset future realized gains. These net capital losses may be carried forward indefinitely and their character is retained as short-term and/or long-term losses. Such losses are characterized as follows:

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| | |
|:---|:---|
| Short-Term | $(21400505)<br>|
| Long-Term | (93637167)<br>|
| Total | $(115037672)<br>|

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**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses.

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

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| | |
|:---|:---|
| Up to $1 billion | 0.90% |
| In excess of $1 billion | 0.80% |

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MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $47,440, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.89% of the fund's average daily net assets.

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses, such that total annual operating expenses do not exceed 0.87% of average daily net assets for the Initial Class shares and 1.12% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027. For the six months ended June 30, 2025, this reduction amounted to $215,423, which is included in the reduction of total expenses in the Statement of Operations.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these

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MFS New Discovery Series

*Notes to Financial Statements (unaudited) - continued* 

participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $13,971, which equated to 0.0041% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,897.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0147% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 12 shares of Service Class for an aggregate amount of $133.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in sale transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $1,522,019. The sales transactions resulted in net realized gains (losses) of $399,229.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $37,816, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $277,572,646 and $299,236,401, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

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| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 1135520 | &nbsp;&nbsp; $14761721 | &nbsp;&nbsp; 1654145 | &nbsp;&nbsp; $22517075 |
| Service Class | 2178121 | &nbsp;&nbsp; 22547109 | &nbsp;&nbsp; 4792292 | &nbsp;&nbsp; 51827318 |
|  | 3313641 | &nbsp;&nbsp; $37308830 | &nbsp;&nbsp; 6446437 | &nbsp;&nbsp; $74344393 |
| Shares reacquired |  |  |  |  |
| Initial Class | (1858210)<br>| &nbsp;&nbsp; $(25408679)<br>| &nbsp;&nbsp; (4168427)<br>| &nbsp;&nbsp; $(56342543)<br>|
| Service Class | (3479026)<br>| &nbsp;&nbsp; (37178283)<br>| &nbsp;&nbsp; (6077841)<br>| &nbsp;&nbsp; (64306639)<br>|
|  | (5337236)<br>| &nbsp;&nbsp; $(62586962)<br>| &nbsp;&nbsp; (10246268)<br>| &nbsp;&nbsp; $(120649182)<br>|
| Net change |  |  |  |  |
| Initial Class | (722690)<br>| &nbsp;&nbsp; $(10646958)<br>| &nbsp;&nbsp; (2514282)<br>| &nbsp;&nbsp; $(33825468)<br>|
| Service Class | (1300905)<br>| &nbsp;&nbsp; (14631174)<br>| &nbsp;&nbsp; (1285549)<br>| &nbsp;&nbsp; (12479321)<br>|

---

------

MFS New Discovery Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | | |
|:---|:---|:---|:---|
| **Six months ended**<br> **6/30/25** | **Six months ended**<br> **6/30/25** | **Year ended**<br> **12/31/24** | **Year ended**<br> **12/31/24** |
| **Shares** | **Amount** | **Shares** | **Amount** |
| (2023595)<br>| &nbsp;&nbsp; $(25278132)<br>| &nbsp;&nbsp; (3799831)<br>| &nbsp;&nbsp; $(46304789)<br>|

---

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio was the owner of record of approximately 2% of the value of outstanding voting shares of the fund. In addition, the MFS Conservative Allocation Portfolio and the MFS Growth Allocation Portfolio were the owners of record of less than 1% of the value of outstanding voting shares of the fund.

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $1,715 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $29058546 | &nbsp;&nbsp; $123305124 | &nbsp;&nbsp; $125162389 | &nbsp;&nbsp; $(2156)<br>| &nbsp;&nbsp; $(2292)<br>| &nbsp;&nbsp; $27196833 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $689672 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS New Discovery Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS New Discovery Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS New Discovery Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Investors Trust Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Investors Trust Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 99.7% | Common Stocks – 99.7% | Common Stocks – 99.7% |
| Aerospace & Defense – 2.6% | Aerospace & Defense – 2.6% |  |
| Howmet Aerospace, Inc. | 25381 | &nbsp;&nbsp; $4724166 |
| RTX Corp. | 20421 | &nbsp;&nbsp; 2981874 |
|  |  | &nbsp;&nbsp; $7706040 |
| Alcoholic Beverages – 0.8% | Alcoholic Beverages – 0.8% |  |
| Diageo PLC | 88512 | &nbsp;&nbsp; $2220946 |
| Apparel Manufacturers – 0.6% | Apparel Manufacturers – 0.6% |  |
| LVMH Moet Hennessy Louis Vuitton SE | 3534 | &nbsp;&nbsp; $1850815 |
| Brokerage & Asset Managers – 2.4% | Brokerage & Asset Managers – 2.4% |  |
| CME Group, Inc. | 17899 | &nbsp;&nbsp; $4933323 |
| NASDAQ, Inc. | 24508 | &nbsp;&nbsp; 2191505 |
|  |  | &nbsp;&nbsp; $7124828 |
| Business Services – 2.1% | Business Services – 2.1% |  |
| Fiserv, Inc. (a) | 28731 | &nbsp;&nbsp; $4953512 |
| TransUnion | 15812 | &nbsp;&nbsp; 1391456 |
|  |  | &nbsp;&nbsp; $6344968 |
| Computer Software – 12.7% | Computer Software – 12.7% |  |
| Check Point Software Technologies Ltd. (a) | 22265 | &nbsp;&nbsp; $4926131 |
| Microsoft Corp. | 54242 | &nbsp;&nbsp; 26980513 |
| Salesforce, Inc. | 21618 | &nbsp;&nbsp; 5895013 |
|  |  | &nbsp;&nbsp; $37801657 |
| Computer Software - Systems – 4.1% | Computer Software - Systems – 4.1% |  |
| Apple, Inc. | 50664 | &nbsp;&nbsp; $10394733 |
| EPAM Systems, Inc. (a) | 10071 | &nbsp;&nbsp; 1780754 |
|  |  | &nbsp;&nbsp; $12175487 |
| Construction – 1.5% | Construction – 1.5% |  |
| Allegion PLC | 19295 | &nbsp;&nbsp; $2780795 |
| Otis Worldwide Corp. | 17440 | &nbsp;&nbsp; 1726909 |
|  |  | &nbsp;&nbsp; $4507704 |
| Consumer Products – 3.4% | Consumer Products – 3.4% |  |
| Colgate-Palmolive Co. | 29120 | &nbsp;&nbsp; $2647008 |
| Kenvue, Inc. | 127103 | &nbsp;&nbsp; 2660266 |
| Procter & Gamble Co. | 30345 | &nbsp;&nbsp; 4834565 |
|  |  | &nbsp;&nbsp; $10141839 |
| Electrical Equipment – 5.1% | Electrical Equipment – 5.1% |  |
| AMETEK, Inc. | 13956 | &nbsp;&nbsp; $2525478 |
| Amphenol Corp., "A" | 20657 | &nbsp;&nbsp; 2039879 |
| Emerson Electric Co. | 28871 | &nbsp;&nbsp; 3849370 |
| Hubbell, Inc. | 5633 | &nbsp;&nbsp; 2300574 |
| TE Connectivity PLC | 27115 | &nbsp;&nbsp; 4573487 |
|  |  | &nbsp;&nbsp; $15288788 |

---

VGIFS-SEM

------

MFS Investors Trust Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Electronics – 10.2% | Electronics – 10.2% |  |
| Analog Devices, Inc. | 14721 | &nbsp;&nbsp; $3503892 |
| ASML Holding N.V. | 2357 | &nbsp;&nbsp; 1881309 |
| KLA Corp. | 1841 | &nbsp;&nbsp; 1649057 |
| Lam Research Corp. | 38025 | &nbsp;&nbsp; 3701354 |
| NVIDIA Corp. | 110143 | &nbsp;&nbsp; 17401493 |
| Texas Instruments, Inc. | 11049 | &nbsp;&nbsp; 2293993 |
|  |  | &nbsp;&nbsp; $30431098 |
| Energy - Independent – 1.4% | Energy - Independent – 1.4% |  |
| ConocoPhillips | 46771 | &nbsp;&nbsp; $4197230 |
| Energy - Integrated – 1.2% | Energy - Integrated – 1.2% |  |
| Exxon Mobil Corp. | 32504 | &nbsp;&nbsp; $3503931 |
| Health Maintenance Organizations – 1.4% | Health Maintenance Organizations – 1.4% |  |
| Cigna Group | 12207 | &nbsp;&nbsp; $4035390 |
| Insurance – 4.2% | Insurance – 4.2% |  |
| Aon PLC | 12409 | &nbsp;&nbsp; $4427035 |
| Chubb Ltd. | 14650 | &nbsp;&nbsp; 4244398 |
| Willis Towers Watson PLC | 12595 | &nbsp;&nbsp; 3860367 |
|  |  | &nbsp;&nbsp; $12531800 |
| Interactive Media Services – 7.9% | Interactive Media Services – 7.9% |  |
| Alphabet, Inc., "A" | 63737 | &nbsp;&nbsp; $11232372 |
| Meta Platforms, Inc., "A" | 16605 | &nbsp;&nbsp; 12255984 |
|  |  | &nbsp;&nbsp; $23488356 |
| Machinery & Tools – 3.3% | Machinery & Tools – 3.3% |  |
| Eaton Corp. PLC | 15612 | &nbsp;&nbsp; $5573328 |
| Veralto Corp. | 14445 | &nbsp;&nbsp; 1458222 |
| Wabtec Corp. | 12528 | &nbsp;&nbsp; 2622737 |
|  |  | &nbsp;&nbsp; $9654287 |
| Major Banks – 5.6% | Major Banks – 5.6% |  |
| Bank of America Corp. | 73097 | &nbsp;&nbsp; $3458950 |
| Goldman Sachs Group, Inc. | 7012 | &nbsp;&nbsp; 4962743 |
| JPMorgan Chase & Co. | 28747 | &nbsp;&nbsp; 8334043 |
|  |  | &nbsp;&nbsp; $16755736 |
| Medical & Health Technology & Services – 0.4% | Medical & Health Technology & Services – 0.4% |  |
| ICON PLC (a) | 8359 | &nbsp;&nbsp; $1215817 |
| Medical Equipment – 6.2% | Medical Equipment – 6.2% |  |
| Abbott Laboratories | 23056 | &nbsp;&nbsp; $3135847 |
| Agilent Technologies, Inc. | 26580 | &nbsp;&nbsp; 3136706 |
| Becton, Dickinson and Co. | 14719 | &nbsp;&nbsp; 2535348 |
| Medtronic PLC | 51614 | &nbsp;&nbsp; 4499192 |
| STERIS PLC | 16312 | &nbsp;&nbsp; 3918469 |
| Thermo Fisher Scientific, Inc. | 2925 | &nbsp;&nbsp; 1185970 |
|  |  | &nbsp;&nbsp; $18411532 |

---

------

MFS Investors Trust Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Other Banks & Diversified Financials – 4.2% | Other Banks & Diversified Financials – 4.2% |  |
| Mastercard, Inc., "A" | 10480 | &nbsp;&nbsp; $5889131 |
| Visa, Inc., "A" | 18259 | &nbsp;&nbsp; 6482858 |
|  |  | &nbsp;&nbsp; $12371989 |
| Pharmaceuticals – 3.0% | Pharmaceuticals – 3.0% |  |
| Johnson & Johnson | 26143 | &nbsp;&nbsp; $3993343 |
| Vertex Pharmaceuticals, Inc. (a) | 9241 | &nbsp;&nbsp; 4114093 |
| Zoetis, Inc. | 5246 | &nbsp;&nbsp; 818114 |
|  |  | &nbsp;&nbsp; $8925550 |
| Pollution Control – 0.7% | Pollution Control – 0.7% |  |
| Waste Management, Inc. | 9231 | &nbsp;&nbsp; $2112237 |
| Restaurants – 1.1% | Restaurants – 1.1% |  |
| Aramark | 74227 | &nbsp;&nbsp; $3107885 |
| Specialty Chemicals – 1.1% | Specialty Chemicals – 1.1% |  |
| Linde PLC | 7151 | &nbsp;&nbsp; $3355106 |
| Specialty Stores – 7.9% | Specialty Stores – 7.9% |  |
| Amazon.com, Inc. (a) | 72511 | &nbsp;&nbsp; $15908188 |
| Costco Wholesale Corp. | 4428 | &nbsp;&nbsp; 4383454 |
| Home Depot, Inc. | 8709 | &nbsp;&nbsp; 3193068 |
|  |  | &nbsp;&nbsp; $23484710 |
| Telecom - Infrastructure – 1.5% | Telecom - Infrastructure – 1.5% |  |
| American Tower Corp., REIT | 20487 | &nbsp;&nbsp; $4528037 |
| Utilities - Electric Power – 3.1% | Utilities - Electric Power – 3.1% |  |
| Alliant Energy Corp. | 39735 | &nbsp;&nbsp; $2402775 |
| Southern Co. | 29032 | &nbsp;&nbsp; 2666009 |
| Xcel Energy, Inc. | 59823 | &nbsp;&nbsp; 4073946 |
|  |  | &nbsp;&nbsp; $9142730 |
| **Total Common Stocks (Identified Cost, $165,926,752)** |  | &nbsp;&nbsp; **$296416493** |
| Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% | Mutual Funds (h) – 0.4% |
| Money Market Funds – 0.4% | Money Market Funds – 0.4% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $1,086,346) | 1086345 | &nbsp;&nbsp; $1086454 |
| Other Assets, Less Liabilities – (0.1)% |  | &nbsp;&nbsp; (209826) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$297293121** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $1,086,454 and $296,416,493, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

The following abbreviations are used in this report and are defined: <br> REIT Real Estate Investment Trust

**See Notes to Financial Statements**

------

MFS Investors Trust Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $165,926,752) | &nbsp;&nbsp; $296416493 |
| Investments in affiliated issuers, at value (identified cost, $1,086,346) | &nbsp;&nbsp; 1086454 |
| Cash | &nbsp;&nbsp; 9927 |
| Receivables for |  |
| Investments sold | &nbsp;&nbsp; 1332623 |
| Fund shares sold | &nbsp;&nbsp; 9894 |
| Dividends | &nbsp;&nbsp; 161987 |
| Receivable from investment adviser | &nbsp;&nbsp; 1125 |
| Other assets | &nbsp;&nbsp; 996 |
| Total assets | &nbsp;&nbsp; $299019499 |
| **Liabilities** |  |
| Payables for |  |
| Investments purchased | &nbsp;&nbsp; $1338150 |
| Fund shares reacquired | &nbsp;&nbsp; 287663 |
| Payable to affiliates |  |
| Administrative services fee | &nbsp;&nbsp; 531 |
| Shareholder servicing costs | &nbsp;&nbsp; 526 |
| Distribution and/or service fees | &nbsp;&nbsp; 2783 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 3278 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 93447 |
| Total liabilities | &nbsp;&nbsp; $1726378 |
| Net assets | &nbsp;&nbsp; $297293121 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $(235136831)<br>|
| Total distributable earnings (loss) | &nbsp;&nbsp; 532429952 |
| Net assets | &nbsp;&nbsp; $297293121 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 7138991 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $194906184 | &nbsp;&nbsp;&nbsp; 4643821 | &nbsp;&nbsp;&nbsp; $41.97 |
| Service Class | &nbsp;&nbsp;&nbsp; 102386937 | &nbsp;&nbsp;&nbsp; 2495170 | &nbsp;&nbsp;&nbsp;&nbsp;41.03 |

---

**See Notes to Financial Statements**

------

MFS Investors Trust Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $2244261 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 123512 |
| Other | &nbsp;&nbsp; 6307 |
| Foreign taxes withheld | &nbsp;&nbsp; (6679)<br>|
| Total investment income | &nbsp;&nbsp; $2367401 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $1510600 |
| Distribution and/or service fees | &nbsp;&nbsp; 208085 |
| Shareholder servicing costs | &nbsp;&nbsp; 8861 |
| Administrative services fee | &nbsp;&nbsp; 32443 |
| Independent Trustees' compensation | &nbsp;&nbsp; 6041 |
| Custodian fee | &nbsp;&nbsp; 21586 |
| Shareholder communications | &nbsp;&nbsp; 24421 |
| Audit and tax fees | &nbsp;&nbsp; 35165 |
| Legal fees | &nbsp;&nbsp; 2052 |
| Miscellaneous | &nbsp;&nbsp; 17298 |
| Total expenses | &nbsp;&nbsp; $1866552 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (166324)<br>|
| Net expenses | &nbsp;&nbsp; $1700228 |
| Net investment income (loss) | &nbsp;&nbsp; $667173 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $277879998 |
| Affiliated issuers | &nbsp;&nbsp; (9136)<br>|
| Foreign currency | &nbsp;&nbsp; 2025 |
| Net realized gain (loss)  | &nbsp;&nbsp; $277872887 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $(248320713)<br>|
| Affiliated issuers | &nbsp;&nbsp; (302)<br>|
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; (18)<br>|
| Net unrealized gain (loss) | &nbsp;&nbsp; $(248321033)<br>|
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $29551854 |
| Change in net assets from operations | &nbsp;&nbsp; $30219027 |

---

**See Notes to Financial Statements**

------

MFS Investors Trust Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $667173 | &nbsp;&nbsp; $3731800 |
| Net realized gain (loss) | 277872887 | &nbsp;&nbsp; 121678666 |
| Net unrealized gain (loss) | (248321033)<br>| &nbsp;&nbsp; 19401901 |
| Change in net assets from operations | $30219027 | &nbsp;&nbsp; $144812367 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(62272068)<br>|
| Change in net assets from fund share transactions | $(550747026)<br>| &nbsp;&nbsp; $(52707577)<br>|
| Total change in net assets | $(520527999)<br>| &nbsp;&nbsp; $29832722 |
| **Net assets** |  |  |
| At beginning of period | 817821120 | &nbsp;&nbsp; 787988398 |
| At end of period | $297293121 | &nbsp;&nbsp; $817821120 |

---

**See Notes to Financial Statements**

------

MFS Investors Trust Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $39.74 | &nbsp;&nbsp; $35.99 | &nbsp;&nbsp; $32.27 | &nbsp;&nbsp; $44.72 | &nbsp;&nbsp; $36.57 | &nbsp;&nbsp; $33.27 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.10 | &nbsp;&nbsp; $0.23 | &nbsp;&nbsp; $0.25 | &nbsp;&nbsp; $0.27 | &nbsp;&nbsp; $0.21 | &nbsp;&nbsp; $0.25 |
| Net realized and unrealized gain (loss) | 2.13 | &nbsp;&nbsp;&nbsp;&nbsp;6.71 | &nbsp;&nbsp;&nbsp;&nbsp;5.69 | &nbsp;&nbsp; (7.41)<br>| &nbsp;&nbsp;&nbsp;&nbsp;9.53 | &nbsp;&nbsp;&nbsp;&nbsp;4.26 |
| Total from investment operations | $2.23 | &nbsp;&nbsp; $6.94 | &nbsp;&nbsp; $5.94 | &nbsp;&nbsp; $(7.14)<br>| &nbsp;&nbsp; $9.74 | &nbsp;&nbsp; $4.51 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.29)<br>| &nbsp;&nbsp; $(0.26)<br>| &nbsp;&nbsp; $(0.26)<br>| &nbsp;&nbsp; $(0.26)<br>| &nbsp;&nbsp; $(0.21)<br>|
| From net realized gain |  | &nbsp;&nbsp; (2.90)<br>| &nbsp;&nbsp; (1.96)<br>| &nbsp;&nbsp; (5.05)<br>| &nbsp;&nbsp; (1.33)<br>| &nbsp;&nbsp; (1.00)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(3.19)<br>| &nbsp;&nbsp; $(2.22)<br>| &nbsp;&nbsp; $(5.31)<br>| &nbsp;&nbsp; $(1.59)<br>| &nbsp;&nbsp; $(1.21)<br>|
| Net asset value, end of period (x) | $41.97 | &nbsp;&nbsp; $39.74 | &nbsp;&nbsp; $35.99 | &nbsp;&nbsp; $32.27 | &nbsp;&nbsp; $44.72 | &nbsp;&nbsp; $36.57 |
| Total return (%) (k)(r)(s)(x) | 5.61<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;19.52 | &nbsp;&nbsp;&nbsp;&nbsp;18.98 | &nbsp;&nbsp; (16.49)<br>| &nbsp;&nbsp;&nbsp;&nbsp;26.81 | &nbsp;&nbsp;&nbsp;&nbsp;13.87 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.82<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 |
| Expenses after expense reductions | 0.74<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.76 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 |
| Net investment income (loss) | 0.51<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.59 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 | &nbsp;&nbsp;&nbsp;&nbsp;0.74 | &nbsp;&nbsp;&nbsp;&nbsp;0.50 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 |
| Portfolio turnover rate | 14<br> (n)<br>| &nbsp;&nbsp; 25 | &nbsp;&nbsp; 20 | &nbsp;&nbsp; 17 | &nbsp;&nbsp; 13 | &nbsp;&nbsp; 19 |
| Net assets at end of period (000 omitted) | $194906 | &nbsp;&nbsp; $410831 | &nbsp;&nbsp; $369577 | &nbsp;&nbsp; $357428 | &nbsp;&nbsp; $296678 | &nbsp;&nbsp; $269852 |

---

**See Notes to Financial Statements**

------

MFS Investors Trust Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $38.89 | &nbsp;&nbsp; $35.28 | &nbsp;&nbsp; $31.67 | &nbsp;&nbsp; $43.97 | &nbsp;&nbsp; $35.99 | &nbsp;&nbsp; $32.77 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.02 | &nbsp;&nbsp; $0.13 | &nbsp;&nbsp; $0.16 | &nbsp;&nbsp; $0.16 | &nbsp;&nbsp; $0.10 | &nbsp;&nbsp; $0.17 |
| Net realized and unrealized gain (loss) | 2.12 | &nbsp;&nbsp;&nbsp;&nbsp;6.57 | &nbsp;&nbsp;&nbsp;&nbsp;5.57 | &nbsp;&nbsp; (7.26)<br>| &nbsp;&nbsp;&nbsp;&nbsp;9.38 | &nbsp;&nbsp;&nbsp;&nbsp;4.19 |
| Total from investment operations | $2.14 | &nbsp;&nbsp; $6.70 | &nbsp;&nbsp; $5.73 | &nbsp;&nbsp; $(7.10)<br>| &nbsp;&nbsp; $9.48 | &nbsp;&nbsp; $4.36 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.19)<br>| &nbsp;&nbsp; $(0.16)<br>| &nbsp;&nbsp; $(0.15)<br>| &nbsp;&nbsp; $(0.17)<br>| &nbsp;&nbsp; $(0.14)<br>|
| From net realized gain |  | &nbsp;&nbsp; (2.90)<br>| &nbsp;&nbsp; (1.96)<br>| &nbsp;&nbsp; (5.05)<br>| &nbsp;&nbsp; (1.33)<br>| &nbsp;&nbsp; (1.00)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(3.09)<br>| &nbsp;&nbsp; $(2.12)<br>| &nbsp;&nbsp; $(5.20)<br>| &nbsp;&nbsp; $(1.50)<br>| &nbsp;&nbsp; $(1.14)<br>|
| Net asset value, end of period (x) | $41.03 | &nbsp;&nbsp; $38.89 | &nbsp;&nbsp; $35.28 | &nbsp;&nbsp; $31.67 | &nbsp;&nbsp; $43.97 | &nbsp;&nbsp; $35.99 |
| Total return (%) (k)(r)(s)(x) | 5.50<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;19.22 | &nbsp;&nbsp;&nbsp;&nbsp;18.66 | &nbsp;&nbsp; (16.69)<br>| &nbsp;&nbsp;&nbsp;&nbsp;26.51 | &nbsp;&nbsp;&nbsp;&nbsp;13.60 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.07<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 |
| Expenses after expense reductions | 0.99<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.01 | &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 |
| Net investment income (loss) | 0.08<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.33 | &nbsp;&nbsp;&nbsp;&nbsp;0.49 | &nbsp;&nbsp;&nbsp;&nbsp;0.44 | &nbsp;&nbsp;&nbsp;&nbsp;0.24 | &nbsp;&nbsp;&nbsp;&nbsp;0.53 |
| Portfolio turnover rate | 14<br> (n)<br>| &nbsp;&nbsp; 25 | &nbsp;&nbsp; 20 | &nbsp;&nbsp; 17 | &nbsp;&nbsp; 13 | &nbsp;&nbsp; 19 |
| Net assets at end of period (000 omitted) | $102387 | &nbsp;&nbsp; $406990 | &nbsp;&nbsp; $418412 | &nbsp;&nbsp; $403177 | &nbsp;&nbsp; $534914 | &nbsp;&nbsp; $496093 |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Investors Trust Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Investors Trust Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or

------

MFS Investors Trust Series

*Notes to Financial Statements (unaudited) - continued* 

market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $296416493 | $— | $— | $296416493 |
| Investment Companies | 1086454 |  |  | 1086454 |
| Total | $297502947 | $— | $— | $297502947 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign

------

MFS Investors Trust Series

*Notes to Financial Statements (unaudited) - continued* 

taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $4640547 |
| Long-term capital gains | &nbsp;&nbsp; 57631521 |
| Total distributions | &nbsp;&nbsp; $62272068 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $169111044 |
| Gross appreciation | &nbsp;&nbsp; 133447776 |
| Gross depreciation | &nbsp;&nbsp; (5055873)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $128391903 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 12045911 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 113452083 |
| Other temporary differences | &nbsp;&nbsp; 13 |
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 376712918 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $30429094 |
| Service Class |  | &nbsp;&nbsp; 31842974 |
| Total | $— | &nbsp;&nbsp; $62272068 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion and up to $2.5 billion | 0.65% |
| In excess of $2.5 billion | 0.60% |

---

------

MFS Investors Trust Series

*Notes to Financial Statements (unaudited) - continued* 

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $27,928, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.74% of the fund's average daily net assets.

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses, such that total annual operating expenses do not exceed 0.74% of average daily net assets for the Initial Class shares and 0.99% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027. For the six months ended June 30, 2025, this reduction amounted to $138,396, which is included in the reduction of total expenses in the Statement of Operations.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $7,827, which equated to 0.0039% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,034.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0161% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 3 shares of Service Class for an aggregate amount of $138.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in purchase transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $917,893.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $6,192, which is included in "Other" income in the Statement of Operations.

------

MFS Investors Trust Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $58,528,376 and $275,848,069, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 75082 | &nbsp;&nbsp; $2871674 | &nbsp;&nbsp; 625896 | &nbsp;&nbsp; $24682679 |
| Service Class | 75569 | &nbsp;&nbsp; 2918750 | &nbsp;&nbsp; 451894 | &nbsp;&nbsp; 17413557 |
|  | 150651 | &nbsp;&nbsp; $5790424 | &nbsp;&nbsp; 1077790 | &nbsp;&nbsp; $42096236 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 787502 | &nbsp;&nbsp; $30429094 |
| Service Class |  |  | &nbsp;&nbsp; 841294 | &nbsp;&nbsp; 31842974 |
|  |  | $— | &nbsp;&nbsp; 1628796 | &nbsp;&nbsp; $62272068 |
| Shares reacquired |  |  |  |  |
| Initial Class | (5768550)<br>| &nbsp;&nbsp; $(235967599)<br>| &nbsp;&nbsp; (1345894)<br>| &nbsp;&nbsp; $(53049895)<br>|
| Service Class | (8044966)<br>| &nbsp;&nbsp; (320569851)<br>| &nbsp;&nbsp; (2689950)<br>| &nbsp;&nbsp; (104025986)<br>|
|  | (13813516)<br>| &nbsp;&nbsp; $(556537450)<br>| &nbsp;&nbsp; (4035844)<br>| &nbsp;&nbsp; $(157075881)<br>|
| Net change |  |  |  |  |
| Initial Class | (5693468)<br>| &nbsp;&nbsp; $(233095925)<br>| &nbsp;&nbsp; 67504 | &nbsp;&nbsp; $2061878 |
| Service Class | (7969397)<br>| &nbsp;&nbsp; (317651101)<br>| &nbsp;&nbsp; (1396762)<br>| &nbsp;&nbsp; (54769455)<br>|
|  | (13662865)<br>| &nbsp;&nbsp; $(550747026)<br>| &nbsp;&nbsp; (1329258)<br>| &nbsp;&nbsp; $(52707577)<br>|

---

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $1,412 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $3241619 | &nbsp;&nbsp; $166943736 | &nbsp;&nbsp; $169089463 | &nbsp;&nbsp; $(9136)<br>| &nbsp;&nbsp; $(302)<br>| &nbsp;&nbsp; $1086454 |

---

------

MFS Investors Trust Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $123512 | $— |

---

**(8) Redemptions In-Kind**

On February 7, 2025, the fund recorded a redemption in-kind of portfolio securities and cash that was valued at $332,918,144. The redeeming shareholder generally receives a pro rata share of the securities held by the fund. The distribution of such securities generated a realized gain of $173,866,148 for the fund, which is included in Net realized gain (loss) in the Statement of Operations. For tax purposes, no gains or losses were recognized with respect to the portfolio securities redeemed in-kind.

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Investors Trust Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Investors Trust Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Investors Trust Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Utilities Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Utilities Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 99.4% | Common Stocks – 99.4% | Common Stocks – 99.4% |
| Energy - Renewables – 2.0% | Energy - Renewables – 2.0% |  |
| EDP Renovaveis S.A. | 2023673 | &nbsp;&nbsp; $22586381 |
| Natural Gas - Distribution – 2.2% | Natural Gas - Distribution – 2.2% |  |
| Atmos Energy Corp. | 157729 | &nbsp;&nbsp; $24307616 |
| Telecom - Infrastructure – 4.0% | Telecom - Infrastructure – 4.0% |  |
| Cellnex Telecom S.A. | 513694 | &nbsp;&nbsp; $19938249 |
| SBA Communications Corp., REIT | 104519 | &nbsp;&nbsp; 24545242 |
|  |  | &nbsp;&nbsp; $44483491 |
| Telecom Services – 1.3% | Telecom Services – 1.3% |  |
| Hellenic Telecommunications Organization S.A. | 324354 | &nbsp;&nbsp; $6166658 |
| Rogers Communications, Inc., "B" (l) | 288199 | &nbsp;&nbsp; 8548087 |
|  |  | &nbsp;&nbsp; $14714745 |
| Utilities - Electric Power – 88.0% | Utilities - Electric Power – 88.0% |  |
| Alliant Energy Corp. | 494157 | &nbsp;&nbsp; $29881674 |
| Ameren Corp. | 428025 | &nbsp;&nbsp; 41107521 |
| American Electric Power Co., Inc. | 403251 | &nbsp;&nbsp; 41841324 |
| CenterPoint Energy, Inc. | 225900 | &nbsp;&nbsp; 8299566 |
| Constellation Energy | 281587 | &nbsp;&nbsp; 90885020 |
| Dominion Energy, Inc. | 742833 | &nbsp;&nbsp; 41984921 |
| DTE Energy Co. | 386764 | &nbsp;&nbsp; 51230759 |
| Duke Energy Corp. | 98688 | &nbsp;&nbsp; 11645184 |
| E.ON SE | 511869 | &nbsp;&nbsp; 9421194 |
| Edison International | 622805 | &nbsp;&nbsp; 32136738 |
| Enel S.p.A. | 2856917 | &nbsp;&nbsp; 27110915 |
| Energias de Portugal S.A. | 3309899 | &nbsp;&nbsp; 14355741 |
| Equatorial Energia S.A. | 437736 | &nbsp;&nbsp; 2897239 |
| Exelon Corp. | 129039 | &nbsp;&nbsp; 5602873 |
| National Grid PLC | 992563 | &nbsp;&nbsp; 14462314 |
| NextEra Energy, Inc. | 1714869 | &nbsp;&nbsp; 119046206 |
| OGE Energy Corp. | 278115 | &nbsp;&nbsp; 12342744 |
| PG&E Corp. | 4244449 | &nbsp;&nbsp; 59167619 |
| Pinnacle West Capital Corp. | 227234 | &nbsp;&nbsp; 20330626 |
| Portland General Electric Co. | 375650 | &nbsp;&nbsp; 15262660 |
| PPL Corp. | 1106369 | &nbsp;&nbsp; 37494845 |
| Public Service Enterprise Group, Inc. | 329194 | &nbsp;&nbsp; 27711551 |
| RWE AG | 993038 | &nbsp;&nbsp; 41444234 |
| Sempra Energy | 650744 | &nbsp;&nbsp; 49306873 |
| Southern Co. | 483687 | &nbsp;&nbsp; 44416977 |
| SSE PLC | 1047786 | &nbsp;&nbsp; 26334232 |
| Vistra Corp. | 293977 | &nbsp;&nbsp; 56975682 |
| Xcel Energy, Inc. | 817056 | &nbsp;&nbsp; 55641514 |
|  |  | &nbsp;&nbsp; $988338746 |

---

VUFFS-SEM

------

MFS Utilities Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Utilities - Water – 1.9% | Utilities - Water – 1.9% |  |
| Companhia de Saneamento Basico do Estado de Sao Paulo | 120800 | &nbsp;&nbsp; $2648746 |
| United Utilities Group PLC | 810704 | &nbsp;&nbsp; 12702756 |
| Veolia Environnement S.A. | 163896 | &nbsp;&nbsp; 5840107 |
|  |  | &nbsp;&nbsp; $21191609 |
| **Total Common Stocks (Identified Cost, $750,520,743)** |  | &nbsp;&nbsp; **$1115622588** |
| Mutual Funds (h) – 0.0% | Mutual Funds (h) – 0.0% | Mutual Funds (h) – 0.0% |
| Money Market Funds – 0.0% | Money Market Funds – 0.0% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $149,125) | 149127 | &nbsp;&nbsp; $149142 |
| Collateral for Securities Loaned – 0.1% | Collateral for Securities Loaned – 0.1% | Collateral for Securities Loaned – 0.1% |
| JPMorgan U.S. Government Money Market Fund - Class IM Shares, 4.26% (j) (Identified Cost, $915,900) | 915900 | &nbsp;&nbsp; $915900 |
| Other Assets, Less Liabilities – 0.5% |  | &nbsp;&nbsp; 5732145 |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$1122419775** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $149,142 and $1,116,538,488, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(j) The rate quoted is the annualized seven-day yield of the fund at period end.

&nbsp;&nbsp;&nbsp;&nbsp;(l) A portion of this security is on loan. See Note 2 for additional information.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

---

| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| REIT | Real Estate Investment Trust |
| Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: | Abbreviations indicate amounts shown in currencies other than the U.S. dollar. All amounts are stated in U.S. dollars unless otherwise indicated. A list of <br> abbreviations is shown below: |
| CAD | Canadian Dollar |
| EUR | Euro |
| GBP | British Pound |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** |
| **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** | **Forward Foreign Currency Exchange Contracts** |
| **Currency** <br>**Purchased** | **Currency** <br>**Purchased** | &nbsp;&nbsp;&nbsp;&nbsp; **Currency** <br>**Sold** | &nbsp;&nbsp;&nbsp;&nbsp; **Currency** <br>**Sold** | **Counterparty** | &nbsp;&nbsp;&nbsp;&nbsp; **Settlement** <br>**Date**<br>| &nbsp;&nbsp;&nbsp; **Unrealized** <br>**Appreciation** <br>&nbsp;&nbsp;&nbsp;&nbsp;**(Depreciation)**<br>|
| **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** |
| CAD | &nbsp;&nbsp; 64852 | USD | 46969 | HSBC Bank | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; $694 |
| CAD | &nbsp;&nbsp; 681496 | USD | 482082 | State Street Corp. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 18777 |
| CAD | &nbsp;&nbsp; 29478 | USD | 21411 | UBS AG | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 254 |
| EUR | &nbsp;&nbsp; 346883 | USD | 396423 | BNP Paribas | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 12619 |
| EUR | &nbsp;&nbsp; 109695 | USD | 120367 | HSBC Bank | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 8985 |
| EUR | &nbsp;&nbsp; 1738165 | USD | 1971643 | Merrill Lynch International | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 77990 |
| EUR | &nbsp;&nbsp; 2131532 | USD | 2444685 | Morgan Stanley Capital Services LLC | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 68804 |
| EUR | &nbsp;&nbsp; 2396202 | USD | 2756207 | State Street Corp. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 69381 |
| GBP | &nbsp;&nbsp; 150900 | USD | 192466 | Barclays Bank PLC | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 14681 |
| GBP | &nbsp;&nbsp; 3165398 | USD | 4299436 | Citibank N.A. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 45853 |
| GBP | &nbsp;&nbsp; 489961 | USD | 672369 | HSBC Bank | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 224 |
| GBP | &nbsp;&nbsp; 2197804 | USD | 2927893 | State Street Corp. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 89136 |
| GBP | &nbsp;&nbsp; 118656 | USD | 156847 | UBS AG | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; 6038 |
|  |  |  |  |  |  | &nbsp;&nbsp;&nbsp;&nbsp; $413436 |

---

------

MFS Utilities Series

*Portfolio of Investments (unaudited) – continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** | **Forward Foreign Currency Exchange Contracts - continued** |
| **Currency**<br> **Purchased** | **Currency**<br> **Purchased** | &nbsp;&nbsp;&nbsp;&nbsp; **Currency**<br> **Sold** | &nbsp;&nbsp;&nbsp;&nbsp; **Currency**<br> **Sold** | **Counterparty** | &nbsp;&nbsp;&nbsp;&nbsp; **Settlement**<br> **Date**<br>| &nbsp;&nbsp;&nbsp; **Unrealized**<br> **Appreciation**<br> &nbsp;&nbsp;&nbsp;&nbsp;**(Depreciation)**<br>|
| **Liability Derivatives** | **Liability Derivatives** | **Liability Derivatives** | **Liability Derivatives** | **Liability Derivatives** | **Liability Derivatives** | **Liability Derivatives** |
| USD | &nbsp;&nbsp; 2111463 | CAD | 2907488 | BNP Paribas | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; $(25368)<br>|
| USD | &nbsp;&nbsp; 1602576 | CAD | 2213959 | Goldman Sachs International | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (24552)<br>|
| USD | &nbsp;&nbsp; 2277224 | CAD | 3143822 | Merrill Lynch International | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (33297)<br>|
| USD | &nbsp;&nbsp; 21901857 | EUR | 19302051 | Barclays Bank PLC | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (859002)<br>|
| USD | &nbsp;&nbsp; 29505748 | EUR | 26007024 | JPMorgan Chase Bank N.A. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (1161574)<br>|
| USD | &nbsp;&nbsp; 7413811 | EUR | 6391769 | Morgan Stanley Capital Services LLC | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (123324)<br>|
| USD | &nbsp;&nbsp; 40886936 | EUR | 36003647 | State Street Corp. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (1568344)<br>|
| USD | &nbsp;&nbsp; 34934943 | GBP | 26757116 | JPMorgan Chase Bank N.A. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (1795810)<br>|
| USD | &nbsp;&nbsp; 18900 | GBP | 14336 | Morgan Stanley Capital Services LLC | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (779)<br>|
| USD | &nbsp;&nbsp; 4382941 | GBP | 3277692 | State Street Corp. | 7/18/2025 | &nbsp;&nbsp;&nbsp;&nbsp; (116501)<br>|
|  |  |  |  |  |  | &nbsp;&nbsp;&nbsp;&nbsp; $(5708551)<br>|

---

At June 30, 2025, the fund had cash collateral of $3,342,000 to cover any collateral or margin obligations for certain derivative contracts. Restricted cash and/or deposits with brokers in the Statement of Assets and Liabilities are comprised of cash collateral.

**See Notes to Financial Statements**

------

MFS Utilities Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value, including $889,341 of securities on loan (identified cost, $751,436,643) | &nbsp;&nbsp; $1116538488 |
| Investments in affiliated issuers, at value (identified cost, $149,125) | &nbsp;&nbsp; 149142 |
| Restricted cash for |  |
| Forward foreign currency exchange contracts | &nbsp;&nbsp; 3342000 |
| Receivables for |  |
| Forward foreign currency exchange contracts | &nbsp;&nbsp; 413436 |
| Investments sold | &nbsp;&nbsp; 8535501 |
| Fund shares sold | &nbsp;&nbsp; 360051 |
| Interest and dividends | &nbsp;&nbsp; 4196956 |
| Other assets | &nbsp;&nbsp; 1365 |
| Total assets | &nbsp;&nbsp; $1133536939 |
| **Liabilities** |  |
| Payables for |  |
| Forward foreign currency exchange contracts | &nbsp;&nbsp; $5708551 |
| Fund shares reacquired | &nbsp;&nbsp; 4214183 |
| Collateral for securities loaned, at value | &nbsp;&nbsp; 915900 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 89888 |
| Administrative services fee | &nbsp;&nbsp; 1677 |
| Shareholder servicing costs | &nbsp;&nbsp; 942 |
| Distribution and/or service fees | &nbsp;&nbsp; 16351 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 4075 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 165597 |
| Total liabilities | &nbsp;&nbsp; $11117164 |
| Net assets | &nbsp;&nbsp; $1122419775 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $713935972 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 408483803 |
| Net assets | &nbsp;&nbsp; $1122419775 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 31081321 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $525783178 | &nbsp;&nbsp;&nbsp; 14368519 | &nbsp;&nbsp;&nbsp; $36.59 |
| Service Class | &nbsp;&nbsp;&nbsp; 596636597 | &nbsp;&nbsp;&nbsp; 16712802 | &nbsp;&nbsp;&nbsp;&nbsp;35.70 |

---

**See Notes to Financial Statements**

------

MFS Utilities Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; $18215463 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 258987 |
| Income on securities loaned | &nbsp;&nbsp; 12216 |
| Other | &nbsp;&nbsp; 11366 |
| Foreign taxes withheld | &nbsp;&nbsp; (370699)<br>|
| Total investment income | &nbsp;&nbsp; $18127333 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $4073158 |
| Distribution and/or service fees | &nbsp;&nbsp; 727202 |
| Shareholder servicing costs | &nbsp;&nbsp; 18147 |
| Administrative services fee | &nbsp;&nbsp; 77122 |
| Independent Trustees' compensation | &nbsp;&nbsp; 12487 |
| Custodian fee | &nbsp;&nbsp; 48984 |
| Shareholder communications | &nbsp;&nbsp; 13267 |
| Audit and tax fees | &nbsp;&nbsp; 37896 |
| Legal fees | &nbsp;&nbsp; 2867 |
| Miscellaneous | &nbsp;&nbsp; 57080 |
| Total expenses | &nbsp;&nbsp; $5068210 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (75995)<br>|
| Net expenses | &nbsp;&nbsp; $4992215 |
| Net investment income (loss) | &nbsp;&nbsp; $13135118 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $2277755 |
| Affiliated issuers | &nbsp;&nbsp; (436)<br>|
| Forward foreign currency exchange contracts | &nbsp;&nbsp; (1204174)<br>|
| Foreign currency | &nbsp;&nbsp; (3934)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $1069211 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $71546890 |
| Affiliated issuers | &nbsp;&nbsp; (2321)<br>|
| Forward foreign currency exchange contracts  | &nbsp;&nbsp; (12683165)<br>|
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 176186 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $59037590 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $60106801 |
| Change in net assets from operations | &nbsp;&nbsp; $73241919 |

---

**See Notes to Financial Statements**

------

MFS Utilities Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $13135118 | &nbsp;&nbsp; $22403534 |
| Net realized gain (loss) | 1069211 | &nbsp;&nbsp; 12549845 |
| Net unrealized gain (loss) | 59037590 | &nbsp;&nbsp; 86249411 |
| Change in net assets from operations | $73241919 | &nbsp;&nbsp; $121202790 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(55843912)<br>|
| Change in net assets from fund share transactions | $(56910448)<br>| &nbsp;&nbsp; $(62450278)<br>|
| Total change in net assets | $16331471 | &nbsp;&nbsp; $2908600 |
| **Net assets** |  |  |
| At beginning of period | 1106088304 | &nbsp;&nbsp; 1103179704 |
| At end of period | $1122419775 | &nbsp;&nbsp; $1106088304 |

---

**See Notes to Financial Statements**

------

MFS Utilities Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $34.22 | &nbsp;&nbsp; $32.25 | &nbsp;&nbsp; $36.32 | &nbsp;&nbsp; $38.31 | &nbsp;&nbsp; $35.33 | &nbsp;&nbsp; $35.18 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.44 | &nbsp;&nbsp; $0.73 | &nbsp;&nbsp; $0.86 | &nbsp;&nbsp; $0.71 | &nbsp;&nbsp; $0.78 | &nbsp;&nbsp; $0.87 |
| Net realized and unrealized gain (loss) | 1.93 | &nbsp;&nbsp;&nbsp;&nbsp;3.03 | &nbsp;&nbsp; (1.75)<br>| &nbsp;&nbsp; (0.32)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.11 | &nbsp;&nbsp;&nbsp;&nbsp;0.99 |
| Total from investment operations | $2.37 | &nbsp;&nbsp; $3.76 | &nbsp;&nbsp; $(0.89)<br>| &nbsp;&nbsp; $0.39 | &nbsp;&nbsp; $4.89 | &nbsp;&nbsp; $1.86 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.80)<br>| &nbsp;&nbsp; $(1.25)<br>| &nbsp;&nbsp; $(0.92)<br>| &nbsp;&nbsp; $(0.65)<br>| &nbsp;&nbsp; $(0.84)<br>|
| From net realized gain |  | &nbsp;&nbsp; (0.99)<br>| &nbsp;&nbsp; (1.93)<br>| &nbsp;&nbsp; (1.46)<br>| &nbsp;&nbsp; (1.26)<br>| &nbsp;&nbsp; (0.87)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.79)<br>| &nbsp;&nbsp; $(3.18)<br>| &nbsp;&nbsp; $(2.38)<br>| &nbsp;&nbsp; $(1.91)<br>| &nbsp;&nbsp; $(1.71)<br>|
| Net asset value, end of period (x) | $36.59 | &nbsp;&nbsp; $34.22 | &nbsp;&nbsp; $32.25 | &nbsp;&nbsp; $36.32 | &nbsp;&nbsp; $38.31 | &nbsp;&nbsp; $35.33 |
| Total return (%) (k)(r)(s)(x) | 6.93<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;11.66 | &nbsp;&nbsp; (2.11)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.76 | &nbsp;&nbsp;&nbsp;&nbsp;14.09 | &nbsp;&nbsp;&nbsp;&nbsp;5.90 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.79<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.80 |
| Expenses after expense reductions | 0.78<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 |
| Net investment income (loss) | 2.53<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;2.15 | &nbsp;&nbsp;&nbsp;&nbsp;2.53 | &nbsp;&nbsp;&nbsp;&nbsp;1.92 | &nbsp;&nbsp;&nbsp;&nbsp;2.16 | &nbsp;&nbsp;&nbsp;&nbsp;2.63 |
| Portfolio turnover rate | 8<br> (n)<br>| &nbsp;&nbsp; 10 | &nbsp;&nbsp; 15 | &nbsp;&nbsp; 29 | &nbsp;&nbsp; 16 | &nbsp;&nbsp; 32 |
| Net assets at end of period (000 omitted) | $525783 | &nbsp;&nbsp; $515811 | &nbsp;&nbsp; $503826 | &nbsp;&nbsp; $549238 | &nbsp;&nbsp; $584216 | &nbsp;&nbsp; $537240 |

---

**See Notes to Financial Statements**

------

MFS Utilities Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $33.42 | &nbsp;&nbsp; $31.54 | &nbsp;&nbsp; $35.57 | &nbsp;&nbsp; $37.58 | &nbsp;&nbsp; $34.69 | &nbsp;&nbsp; $34.56 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.39 | &nbsp;&nbsp; $0.63 | &nbsp;&nbsp; $0.76 | &nbsp;&nbsp; $0.60 | &nbsp;&nbsp; $0.68 | &nbsp;&nbsp; $0.77 |
| Net realized and unrealized gain (loss) | 1.89 | &nbsp;&nbsp;&nbsp;&nbsp;2.95 | &nbsp;&nbsp; (1.71)<br>| &nbsp;&nbsp; (0.32)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.03 | &nbsp;&nbsp;&nbsp;&nbsp;0.97 |
| Total from investment operations | $2.28 | &nbsp;&nbsp; $3.58 | &nbsp;&nbsp; $(0.95)<br>| &nbsp;&nbsp; $0.28 | &nbsp;&nbsp; $4.71 | &nbsp;&nbsp; $1.74 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.71)<br>| &nbsp;&nbsp; $(1.15)<br>| &nbsp;&nbsp; $(0.83)<br>| &nbsp;&nbsp; $(0.56)<br>| &nbsp;&nbsp; $(0.74)<br>|
| From net realized gain |  | &nbsp;&nbsp; (0.99)<br>| &nbsp;&nbsp; (1.93)<br>| &nbsp;&nbsp; (1.46)<br>| &nbsp;&nbsp; (1.26)<br>| &nbsp;&nbsp; (0.87)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.70)<br>| &nbsp;&nbsp; $(3.08)<br>| &nbsp;&nbsp; $(2.29)<br>| &nbsp;&nbsp; $(1.82)<br>| &nbsp;&nbsp; $(1.61)<br>|
| Net asset value, end of period (x) | $35.70 | &nbsp;&nbsp; $33.42 | &nbsp;&nbsp; $31.54 | &nbsp;&nbsp; $35.57 | &nbsp;&nbsp; $37.58 | &nbsp;&nbsp; $34.69 |
| Total return (%) (k)(r)(s)(x) | 6.82<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;11.34 | &nbsp;&nbsp; (2.33)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.48 | &nbsp;&nbsp;&nbsp;&nbsp;13.82 | &nbsp;&nbsp;&nbsp;&nbsp;5.62 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 1.04<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 | &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.05 |
| Expenses after expense reductions | 1.03<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.03 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.02 | &nbsp;&nbsp;&nbsp;&nbsp;1.04 |
| Net investment income (loss) | 2.28<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;1.91 | &nbsp;&nbsp;&nbsp;&nbsp;2.28 | &nbsp;&nbsp;&nbsp;&nbsp;1.66 | &nbsp;&nbsp;&nbsp;&nbsp;1.91 | &nbsp;&nbsp;&nbsp;&nbsp;2.38 |
| Portfolio turnover rate | 8<br> (n)<br>| &nbsp;&nbsp; 10 | &nbsp;&nbsp; 15 | &nbsp;&nbsp; 29 | &nbsp;&nbsp; 16 | &nbsp;&nbsp; 32 |
| Net assets at end of period (000 omitted) | $596637 | &nbsp;&nbsp; $590277 | &nbsp;&nbsp; $599354 | &nbsp;&nbsp; $701436 | &nbsp;&nbsp; $711867 | &nbsp;&nbsp; $679629 |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Utilities Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Utilities Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued. The fund invests primarily in securities of issuers in the utility industry. Issuers in a single industry can react similarly to market, currency, political, economic, regulatory, geopolitical, environmental, public health, and other conditions. The value of stocks in the utilities sector can be very volatile due to supply and/or demand for services or fuel, financing costs, conservation efforts, commodity prices, the negative impact of regulation, and other factors. The fund invests in foreign securities. Investments in foreign securities are vulnerable to the effects of changes in the relative values of the local currency and the U.S. dollar and to the effects of changes in each country's market, economic, industrial, political, regulatory, geopolitical, environmental, public health, and other conditions.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Forward foreign currency exchange contracts are generally valued at the mean of bid and asked prices for the time period interpolated from rates provided by a third-party pricing service for proximate time periods. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments, such as forward foreign currency exchange contracts. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $1115622588 | $— | $— | $1115622588 |
| Investment Companies | 1065042 |  |  | 1065042 |
| Total | $1116687630 | $— | $— | $1116687630 |

---

---

| | | | |
|:---|:---|:---|:---|
| **Other Financial Instruments** |  |  |  |
| Forward Foreign Currency Exchange <br> Contracts – Assets<br>| $— | $413436 | $413436 |
| Forward Foreign Currency Exchange <br> Contracts – Liabilities<br>|  | (5708551)<br>| (5708551)<br>|

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

**Derivatives** — The fund uses derivatives primarily to increase or decrease exposure to a particular market or segment of the market, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives are used for hedging or non-hedging purposes. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. When the fund uses derivatives as an investment to increase market exposure, or for hedging purposes, gains and losses from derivative instruments may be substantially greater than the derivative's original cost.

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

The derivative instruments used by the fund during the period were forward foreign currency exchange contracts. Depending on the type of derivative, a fund may exit a derivative position by entering into an offsetting transaction with a counterparty or exchange, negotiating an agreement with the derivative counterparty, or novating the position to a third party. The fund's period end derivatives, as presented in the Portfolio of Investments and the associated Derivative Contract tables, generally are indicative of the volume of its derivative activity during the period.

The following table presents, by major type of derivative contract, the fair value, on a gross basis, of the asset and liability components of derivatives held by the fund at June 30, 2025 as reported in the Statement of Assets and Liabilities:

---

| | | | |
|:---|:---|:---|:---|
|  |  | **Fair Value** | **Fair Value** |
| **Risk** | **Derivative Contracts** | **Asset Derivatives** | **Liability Derivatives** |
| Foreign Exchange | Forward Foreign Currency Exchange Contracts | $413436 | $(5708551) |

---

The following table presents, by major type of derivative contract, the realized gain (loss) on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Forward Foreign** <br>**Currency** <br>**Exchange** <br>**Contracts**<br>|
| Foreign Exchange | $(1204174)<br>|

---

The following table presents, by major type of derivative contract, the change in unrealized appreciation or depreciation on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Forward Foreign** <br>**Currency** <br>**Exchange** <br>**Contracts**<br>|
| Foreign Exchange | $(12683165)<br>|

---

Derivative counterparty credit risk is managed through formal evaluation of the creditworthiness of all potential counterparties. On certain, but not all, uncleared derivatives, the fund attempts to reduce its exposure to counterparty credit risk whenever possible by entering into an ISDA Master Agreement on a bilateral basis. The ISDA Master Agreement gives each party to the agreement the right to terminate all transactions traded under such agreement if there is a specified deterioration in the credit quality of the other party. Upon an event of default or a termination of the ISDA Master Agreement, the non-defaulting party has the right to close out all transactions traded under such agreement and to net amounts owed under each agreement to one net amount payable by one party to the other. This right to close out and net payments across all transactions traded under the ISDA Master Agreement could result in a reduction of the fund's credit risk to such counterparty equal to any amounts payable by the fund under the applicable transactions, if any.

Collateral and margin requirements differ by type of derivative. For exchange-traded and cleared derivatives (e.g., futures contracts, cleared swaps, and exchange-traded options), margin requirements are set by the exchange or clearing broker and the clearing house and collateral, in the form of cash or securities, is posted by the fund directly with the exchange or clearing broker. Collateral terms are counterparty agreement specific for uncleared derivatives (e.g., forward foreign currency exchange contracts, uncleared swap agreements, and uncleared options). Collateral, in the form of cash and securities, is held in segregated accounts with the fund's custodian in connection with these agreements. For derivatives traded under an ISDA Master Agreement, which contains a credit support annex, the collateral requirements are netted across all transactions traded under such counterparty-specific agreement and an amount is posted from one party to the other to collateralize such obligations. Cash that has been segregated or delivered to cover the fund's collateral or margin obligations under derivative contracts, if any, will be reported separately in the Statement of Assets and Liabilities as restricted cash for uncleared derivatives and/or deposits with brokers for exchange-traded or cleared derivatives. Securities pledged as collateral or margin for the same purpose, if any, are noted in the Portfolio of Investments. The fund may be required to make payments of interest on uncovered collateral or margin obligations with the broker. Any such payments are included in "Miscellaneous" expense in the Statement of Operations.

**Forward Foreign Currency Exchange Contracts** — The fund entered into forward foreign currency exchange contracts for the purchase or sale of a specific foreign currency at a fixed price on a future date. These contracts may be used to hedge the fund's currency risk or for non-hedging purposes. For hedging purposes, the fund may enter into contracts to deliver or receive foreign currency that the fund will receive from or use in its normal investment activities. The fund may also use contracts to hedge against

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

declines in the value of foreign currency denominated securities due to unfavorable exchange rate movements. For non-hedging purposes, the fund may enter into contracts with the intent of changing the relative exposure of the fund's portfolio of securities to different currencies to take advantage of anticipated exchange rate changes.

Forward foreign currency exchange contracts are adjusted by the daily exchange rate of the underlying currency and any unrealized gains or losses are recorded as a receivable or payable for forward foreign currency exchange contracts until the contract settlement date. On contract settlement date, any gain or loss on the contract is recorded as realized gains or losses on forward foreign currency exchange contracts.

Risks may arise upon entering into these contracts from unanticipated movements in the value of the contract and from the potential inability of counterparties to meet the terms of their contracts. Generally, the fund's maximum risk due to counterparty credit risk is the unrealized gain on the contract due to the use of Continuous Linked Settlement, a multicurrency cash settlement system for the centralized settlement of foreign transactions. This risk is mitigated in cases where there is an ISDA Master Agreement between the fund and the counterparty providing for netting as described above and, where applicable, by the posting of collateral by the counterparty to the fund to cover the fund's exposure to the counterparty under such ISDA Master Agreement.

**Security Loans** — Under its Securities Lending Agency Agreement with the fund, Goldman Sachs Agency Lending, as lending agent, loans the securities of the fund to certain qualified institutions (the "Borrowers") approved by the fund. Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returned within the earlier of the standard trade settlement period for such securities or within five business days. The loans are collateralized by cash and/or U.S. government securities in an amount typically at least equal to the market value of the securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of the loaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund on the next business day. The lending agent provides the fund with indemnification against Borrower default. In the event of Borrower default, the lending agent will, for the benefit of the fund, either purchase securities identical to those loaned or pay the fund the market value of the loaned securities. In return, the lending agent assumes the fund's rights to the related collateral. If the collateral value is less than the cost to purchase identical securities or the cash needed to pay their market value, the lending agent is responsible for the shortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment for which the fund bears the risk of loss. At period end, the fund had investment securities on loan, all of which were classified as equity securities in the fund's Portfolio of Investments, with a fair value of $889,341. The fair value of the fund's investment securities on loan and a related liability of $915,900 for the obligation to return cash collateral received on securities loaned are both presented gross in the Statement of Assets and Liabilities. The collateral on securities loaned exceeded the value of securities on loan at period end. The liability for cash collateral for securities loaned is carried at fair value, which is categorized as level 2 within the fair value hierarchy. A portion of the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated between the fund and the lending agent. On loans collateralized by U.S. government securities, a fee is received from the Borrower, and is allocated between the fund and the lending agent. Income from securities lending is separately reported in the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the same manner as other dividend and interest income.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Interest income is recorded on the accrual basis. Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to wash sale loss deferrals and derivative transactions.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $24122904 |
| Long-term capital gains | &nbsp;&nbsp; 31721008 |
| Total distributions | &nbsp;&nbsp; $55843912 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $757055082 |
| Gross appreciation | &nbsp;&nbsp; 376411883 |
| Gross depreciation | &nbsp;&nbsp; (16779335)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $359632548 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 34814190 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 12499969 |
| Other temporary differences | &nbsp;&nbsp; (101788)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 288029513 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $26323861 |
| Service Class |  | &nbsp;&nbsp; 29520051 |
| Total | $— | &nbsp;&nbsp; $55843912 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.75% |
| In excess of $1 billion and up to $3 billion | 0.70% |
| In excess of $3 billion | 0.65% |

---

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $75,995, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.73% of the fund's average daily net assets.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $16,333, which equated to 0.0030% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,814.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0141% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 4 shares of Service Class for an aggregate amount of $154.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $11,196, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, aggregated $84,367,296 and $114,367,908, respectively.

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

------

MFS Utilities Series

*Notes to Financial Statements (unaudited) - continued* 

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 297258 | &nbsp;&nbsp; $10339998 | &nbsp;&nbsp; 937033 | &nbsp;&nbsp; $31778473 |
| Service Class | 609381 | &nbsp;&nbsp; 20657682 | &nbsp;&nbsp; 1234911 | &nbsp;&nbsp; 40842973 |
|  | 906639 | &nbsp;&nbsp; $30997680 | &nbsp;&nbsp; 2171944 | &nbsp;&nbsp; $72621446 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 770830 | &nbsp;&nbsp; $26323861 |
| Service Class |  |  | &nbsp;&nbsp; 884363 | &nbsp;&nbsp; 29520051 |
|  |  | $— | &nbsp;&nbsp; 1655193 | &nbsp;&nbsp; $55843912 |
| Shares reacquired |  |  |  |  |
| Initial Class | (1003352)<br>| &nbsp;&nbsp; $(34974961)<br>| &nbsp;&nbsp; (2255434)<br>| &nbsp;&nbsp; $(76435919)<br>|
| Service Class | (1557288)<br>| &nbsp;&nbsp; (52933167)<br>| &nbsp;&nbsp; (3464162)<br>| &nbsp;&nbsp; (114479717)<br>|
|  | (2560640)<br>| &nbsp;&nbsp; $(87908128)<br>| &nbsp;&nbsp; (5719596)<br>| &nbsp;&nbsp; $(190915636)<br>|
| Net change |  |  |  |  |
| Initial Class | (706094)<br>| &nbsp;&nbsp; $(24634963)<br>| &nbsp;&nbsp; (547571)<br>| &nbsp;&nbsp; $(18333585)<br>|
| Service Class | (947907)<br>| &nbsp;&nbsp; (32275485)<br>| &nbsp;&nbsp; (1344888)<br>| &nbsp;&nbsp; (44116693)<br>|
|  | (1654001)<br>| &nbsp;&nbsp; $(56910448)<br>| &nbsp;&nbsp; (1892459)<br>| &nbsp;&nbsp; $(62450278)<br>|

---

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $2,741 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $23322150 | &nbsp;&nbsp; $79730675 | &nbsp;&nbsp; $102900926 | &nbsp;&nbsp; $(436)<br>| &nbsp;&nbsp; $(2321)<br>| &nbsp;&nbsp; $149142 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $258987 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Utilities Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Utilities Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Utilities Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Total Return Bond Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Total Return Bond Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – 98.2% | Bonds – 98.2% | Bonds – 98.2% |
| Aerospace & Defense – 1.3% | Aerospace & Defense – 1.3% | Aerospace & Defense – 1.3% |
| Boeing Co., 2.196%, 2/04/2026  | $6236000 | &nbsp;&nbsp; $6138670 |
| Boeing Co., 5.15%, 5/01/2030  | 1704000 | &nbsp;&nbsp; 1734842 |
| Boeing Co., 6.528%, 5/01/2034  | 4067000 | &nbsp;&nbsp; 4418911 |
| Boeing Co., 5.705%, 5/01/2040  | 1595000 | &nbsp;&nbsp; 1575762 |
| TransDigm, Inc., 4.625%, 1/15/2029  | 5158000 | &nbsp;&nbsp; 5061019 |
|  |  | &nbsp;&nbsp; $18929204 |
| Asset-Backed & Securitized – 19.5% | Asset-Backed & Securitized – 19.5% | Asset-Backed & Securitized – 19.5% |
| ACREC 2025-FL3 LLC, "AS", FLR, 5.954% (SOFR - 1mo. + 1.64%), 8/18/2042 (n) | $3857000 | &nbsp;&nbsp; $3843500 |
| ACREC 2021-FL1 Ltd., "C", FLR, 6.579% ((SOFR - 1mo. + 0.11448%) + 2.15%), 10/16/2036 (n) | 2546000 | &nbsp;&nbsp; 2546899 |
| ACREC 2021-FL1 Ltd., "D", FLR, 7.079% ((SOFR - 1mo. + 0.11448%) + 2.65%), 10/16/2036 (n) | 3070500 | &nbsp;&nbsp; 3052790 |
| Affirm, Inc., 5.08%, 4/15/2030 (n) | 928903 | &nbsp;&nbsp; 929773 |
| American Credit Acceptance Receivables Trust, 2024-2, "B", 6.1%, 12/13/2027 (n) | 2504000 | &nbsp;&nbsp; 2516280 |
| AmeriCredit Automobile Receivables Trust, 2024-1, "A2-A", 5.75%, 2/18/2028  | 1040035 | &nbsp;&nbsp; 1042366 |
| Angel Oak Mortgage Trust, 2024-10, "A1", 5.348%, 10/25/2069 (n) | 4678816 | &nbsp;&nbsp; 4668471 |
| Angel Oak Mortgage Trust, 2024-12, "A1", 5.653%, 10/25/2069 (n) | 4237169 | &nbsp;&nbsp; 4247250 |
| Angel Oak Mortgage Trust, 2024-9, "A1", 5.138%, 9/25/2069 (n) | 2632649 | &nbsp;&nbsp; 2618658 |
| Arbor Realty Trust, Inc., CLO, 2021-FL3, "C", FLR, 6.276% ((SOFR - 1mo. + 0.11448%) + 1.85%), 8/15/2034 (n) | 1740000 | &nbsp;&nbsp; 1732271 |
| Arbor Realty Trust, Inc., CLO, 2021-FL3, "D", FLR, 6.626% ((SOFR - 1mo. + 0.11448%) + 2.2%), 8/15/2034 (n) | 964500 | &nbsp;&nbsp; 958031 |
| Arbor Realty Trust, Inc., CLO, 2021-FL4, "C", FLR, 6.726% ((SOFR - 1mo. + 0.11448%) + 2.3%), 11/15/2036 (n) | 3443500 | &nbsp;&nbsp; 3453761 |
| Arbor Realty Trust, Inc., CLO, 2022-FL1, "D", FLR, 7.303% (SOFR - 30 day + 3%), 1/15/2037 (n) | 9290000 | &nbsp;&nbsp; 9245684 |
| ARDN Mortgage Trust, 2025-ARCP, "B", FLR, 6.3% (SOFR - 1mo. + 2%), 6/15/2035 (n) | 5153000 | &nbsp;&nbsp; 5155234 |
| AREIT 2022-CRE6 Trust, "B", FLR, 6.151% (SOFR - 30 day + 1.85%), 1/20/2037 (n) | 1126000 | &nbsp;&nbsp; 1117441 |
| AREIT 2022-CRE6 Trust, "C", FLR, 6.451% (SOFR - 30 day + 2.15%), 1/20/2037 (n) | 2322000 | &nbsp;&nbsp; 2299385 |
| AREIT 2022-CRE6 Trust, "D", FLR, 7.151% (SOFR - 30 day + 2.85%), 1/20/2037 (n) | 987000 | &nbsp;&nbsp; 978848 |
| AREIT 2025-CRE10 Ltd., "AS", FLR, 5.855% (SOFR - 1mo. + 1.5421%), 1/17/2030 (n) | 4001064 | &nbsp;&nbsp; 3977299 |
| ARI Fleet Lease Trust, 2023-B, "A2", 6.05%, 7/15/2032 (n) | 470477 | &nbsp;&nbsp; 474238 |
| Bayview Commercial Asset Trust, 0%, 12/25/2036 (i)(n) | 44696 | &nbsp;&nbsp; 4 |
| Bayview Financial Revolving Mortgage Loan Trust, FLR, 6.041% ((SOFR - 1mo. + 0.11448%) + 1.6%), 12/28/2040 (n) | 13192 | &nbsp;&nbsp; 26965 |
| BBCMS Mortgage Trust, 2019-C5, "A4", 3.063%, 11/15/2052  | 2755000 | &nbsp;&nbsp; 2588993 |
| BDS 2024-FL13 Ltd., "A", FLR, 5.893% (SOFR - 1mo. + 1.5762%), 9/19/2039 (n) | 1224500 | &nbsp;&nbsp; 1227516 |
| BDS 2025-FL14 Ltd., "B", FLR, 6.01% (SOFR - 1mo. + 1.6926%), 10/21/2042 (n) | 2443148 | &nbsp;&nbsp; 2406122 |
| Benchmark 2023-V3 Mortgage Trust, "A3", 6.363%, 7/15/2056  | 991415 | &nbsp;&nbsp; 1039112 |
| Black Diamond CLO Ltd., 2019-2A, "A2R", FLR, 6.479% (SOFR - 3mo. + 2.2%), 7/23/2032 (n) | 4661659 | &nbsp;&nbsp; 4664652 |
| Brazos Securitization LLC, 5.413%, 9/01/2050 (n) | 3427000 | &nbsp;&nbsp; 3279580 |
| BSPDF 2021-FL1 Issuer Ltd., "B", FLR, 6.226% ((SOFR - 1mo. + 0.11448%) + 1.8%), 10/15/2036 (n) | 3510955 | &nbsp;&nbsp; 3485244 |
| BSPRT 2021-FL6 Issuer Ltd., "B", FLR, 6.026% ((SOFR - 1mo. + 0.11448%) + 1.6%), 3/15/2036 (n) | 3669500 | &nbsp;&nbsp; 3645428 |
| BSPRT 2021-FL6 Issuer Ltd., "C", FLR, 6.476% ((SOFR - 1mo. + 0.11448%) + 2.05%), 3/15/2036 (n) | 1288000 | &nbsp;&nbsp; 1274716 |
| BSPRT 2021-FL7 Issuer Ltd., "C", FLR, 6.726% ((SOFR - 1mo. + 0.11448%) + 2.3%), 12/15/2038 (n) | 836500 | &nbsp;&nbsp; 828807 |
| BSPRT 2021-FL7 Issuer Ltd., "D", FLR, 7.176% ((SOFR - 1mo. + 0.11448%) + 2.75%), 12/15/2038 (n) | 952500 | &nbsp;&nbsp; 936351 |
| Business Jet Securities LLC, 2024-1A, "A", 6.197%, 5/15/2039 (n) | 851520 | &nbsp;&nbsp; 869826 |
| Business Jet Securities LLC, 2024-1A, "B", 6.924%, 5/15/2039 (n) | 120013 | &nbsp;&nbsp; 123184 |
| BXMT 2020-FL2 Ltd., "B", FLR, 6.078% ((SOFR - 1mo. + 0.11448%) + 1.4%), 2/15/2038 (n) | 1731000 | &nbsp;&nbsp; 1707486 |
| Cantor Commercial Real Estate, 2019-CF2, "A5", 2.874%, 11/15/2052  | 6645635 | &nbsp;&nbsp; 6171586 |
| Chesapeake Funding II LLC, 2023-1A, "A1", 5.65%, 5/15/2035 (n) | 553688 | &nbsp;&nbsp; 556432 |
| Citigroup Commercial Mortgage Trust, 2016-P6, "A5", 3.72%, 12/10/2049  | 1754000 | &nbsp;&nbsp; 1711452 |
| Colt Funding LLC, 2024-5, "A1", 5.123%, 8/25/2069 (n) | 3088366 | &nbsp;&nbsp; 3076451 |
| Columbia Cent CLO Ltd., 2021-31A, FLR, 6.119% (SOFR - 3mo. + 1.85%), 4/20/2034 (n) | 2457213 | &nbsp;&nbsp; 2441565 |
| Commercial Mortgage Pass-Through Certificates, 2023-BNK46, "A4", 5.745%, 8/15/2056  | 4656029 | &nbsp;&nbsp; 4875446 |
| Commercial Mortgage Pass-Through Certificates, 2023-BNK46, "AS", 6.385%, 8/15/2056  | 2699147 | &nbsp;&nbsp; 2895815 |
| Consumers 2023 Securitization Funding LLC, 5.55%, 3/01/2028  | 1502479 | &nbsp;&nbsp; 1512999 |

---

VFBFS-SEM

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued |
| Credit Acceptance Auto Loan Trust, 2023-3A, "A", 6.39%, 8/15/2033 (n) | $973000 | &nbsp;&nbsp; $981553 |
| Deephaven Residential Mortgage Trust, 2024-1A, "A", 5.735%, 7/25/2069 (n) | 5938924 | &nbsp;&nbsp; 5970654 |
| DLLST LLC, 2024-1A, "A2", 5.33%, 1/20/2026 (n) | 165625 | &nbsp;&nbsp; 165734 |
| ELM Trust, 2024-ELM, "C10", 6.189%, 6/10/2039 (n) | 742347 | &nbsp;&nbsp; 745171 |
| ELM Trust, 2024-ELM, "C15", 6.189%, 6/10/2039 (n) | 1011934 | &nbsp;&nbsp; 1015603 |
| Empire District Bondco LLC, 4.943%, 1/01/2033  | 1496081 | &nbsp;&nbsp; 1506456 |
| Enterprise Fleet Financing 2023-3 LLC, "A2", 6.4%, 3/20/2030 (n) | 1394128 | &nbsp;&nbsp; 1415064 |
| Enterprise Fleet Financing 2024-4 LLC, "A2", 4.69%, 7/20/2027 (n) | 1153000 | &nbsp;&nbsp; 1154541 |
| Exeter Automobile Receivables Trust, 2025-1A, "A", 4.7%, 9/15/2027  | 2008060 | &nbsp;&nbsp; 2008127 |
| GLS Auto Select Receivables Trust, 2023-2A, 6.37%, 6/15/2028 (n) | 568822 | &nbsp;&nbsp; 573166 |
| GLS Auto Select Receivables Trust, 2025-2A, "A2", 4.75%, 3/15/2028 (n) | 494000 | &nbsp;&nbsp; 494343 |
| HarbourView CLO VII Ltd., 7RA, "B", FLR, 6.231% ((SOFR - 3mo. + 0.26161%) + 1.7%), 7/18/2031 (n) | 6545000 | &nbsp;&nbsp; 6546394 |
| Hyundai Auto Lease Securitization Trust, 2025-B, 4.58%, 9/15/2027 (n) | 1877000 | &nbsp;&nbsp; 1883412 |
| ILPT Commercial Mortgage Trust, 2025-LPF2, "A", 5.292%, 7/13/2042 (n) | 3609000 | &nbsp;&nbsp; 3650329 |
| JPMorgan Mortgage Trust, "A1", 5.048%, 10/25/2033  | 18759 | &nbsp;&nbsp; 17889 |
| KKR Static CLO Ltd., 2022-1A, "BR2", FLR, 5.719% (SOFR - 3mo. + 1.45%), 7/20/2031 (n) | 3690506 | &nbsp;&nbsp; 3678353 |
| Kubota Credit Owner Trust, 2023-2A, "A2", 5.61%, 7/15/2026 (n) | 145181 | &nbsp;&nbsp; 145333 |
| LoanCore 2021-CRE5 Ltd., "AS", FLR, 6.176% ((SOFR - 1mo. + 0.11448%) + 1.75%), 7/15/2036 (n) | 5666000 | &nbsp;&nbsp; 5663998 |
| LoanCore 2021-CRE5 Ltd., "B", FLR, 6.426% ((SOFR - 1mo. + 0.11448%) + 2.0%), 7/15/2036 (n) | 5318000 | &nbsp;&nbsp; 5294495 |
| LoanCore 2021-CRE6 Ltd., "B", FLR, 6.326% ((SOFR - 1mo. + 0.11448%) + 1.9%), 11/15/2038 (n) | 9970000 | &nbsp;&nbsp; 9970110 |
| LoanCore 2025-CRE8 Ltd., "AS", FLR, 5.904% (SOFR - 1mo. + 1.5909%), 8/17/2042 (n) | 7367000 | &nbsp;&nbsp; 7309430 |
| Madison Park Funding Ltd., 2017-23A, "CR", FLR, 6.544% ((SOFR - 3mo. + 0.26161%) + 2%), 7/27/2031 (n) | 5894060 | &nbsp;&nbsp; 5912408 |
| Man GLG US CLO, 2018-2 Ltd., "B", FLR, 7.272% (SOFR - 3mo. + 3%), 7/20/2035 (n) | 3420864 | &nbsp;&nbsp; 3430227 |
| Merrill Lynch Mortgage Investors, Inc., "A", 5.994%, 5/25/2036  | 14479 | &nbsp;&nbsp; 14173 |
| Merrill Lynch Mortgage Investors, Inc., "A5", 5.154%, 4/25/2035  | 52066 | &nbsp;&nbsp; 46749 |
| MF1 2020-FL4 Ltd., "AS", FLR, 6.528% ((SOFR - 1mo. + 0.11448%) + 2.1%), 12/15/2035 (n) | 2602500 | &nbsp;&nbsp; 2603312 |
| MF1 2021-FL5 Ltd., "C", FLR, 6.128% ((SOFR - 1mo. + 0.11448%) + 1.7%), 7/15/2036 (n) | 2589000 | &nbsp;&nbsp; 2581953 |
| MF1 2022-FL8 Ltd., "C", FLR, 6.517% (SOFR - 30 day + 2.2%), 2/19/2037 (n) | 2433741 | &nbsp;&nbsp; 2419487 |
| MF1 2022-FL8 Ltd., "D", FLR, 6.967% (SOFR - 30 day + 2.65%), 2/19/2037 (n) | 1407473 | &nbsp;&nbsp; 1389897 |
| MF1 2024-FL14 LLC, "AS", FLR, 6.557% (SOFR - 1mo. + 2.24%), 3/19/2039 (n) | 3688167 | &nbsp;&nbsp; 3692449 |
| MF1 2024-FL15 LLC, "AS", FLR, 6.355% (SOFR - 1mo. + 2.04%), 8/18/2041 (n) | 4032000 | &nbsp;&nbsp; 4045860 |
| MF1 2024-FL16 LLC, "AS", FLR, 6.256% (SOFR - 1mo. + 1.942%), 11/18/2039 (n) | 4385479 | &nbsp;&nbsp; 4399192 |
| MF1 2025-FL17 LLC, "B", FLR, 6.106% (SOFR - 1mo. + 1.792%), 2/18/2040 (n) | 2388514 | &nbsp;&nbsp; 2368388 |
| MF1 2025-FL19 LLC, "A", FLR, 5.886% (SOFR - 1mo. + 1.572%), 2/18/2040 (n) | 3775488 | &nbsp;&nbsp; 3747980 |
| MF1 2025-FL19 LLC, "A", FLR, 5.802% (SOFR - 1mo. + 1.4881%), 5/18/2042 (n) | 3778621 | &nbsp;&nbsp; 3783339 |
| Morgan Stanley Residential Mortgage Loan Trust, 2024-NQM1, "A-1", 6.152%, 12/25/2068 (n) | 2412200 | &nbsp;&nbsp; 2429821 |
| MSWF Commercial Mortgage Trust, 2023-2, "A5", 6.014%, 12/15/2056  | 3231641 | &nbsp;&nbsp; 3460890 |
| Neuberger Berman CLO Ltd., 2013-15A, "CR2", FLR, 6.367% ((SOFR - 3mo. + 0.26161%) + 1.85%), 10/15/2029 (n) | 7481614 | &nbsp;&nbsp; 7487966 |
| Northwoods Capital Ltd., 2018-14BA, "BR", FLR, 6.158% (SOFR - 3mo. + 1.85%), 11/13/2031 (n) | 3306562 | &nbsp;&nbsp; 3308820 |
| OBX Trust, 2024-NQM15, "A1", 5.316%, 10/25/2064 (n) | 1794654 | &nbsp;&nbsp; 1791304 |
| OBX Trust, 2024-NQM9, "A1", 6.03%, 1/25/2064 (n) | 2532056 | &nbsp;&nbsp; 2553960 |
| PFP III 2024-11 Ltd., "11A", FLR, 6.143% (SOFR - 1mo. + 1.83239%), 9/17/2039 (n) | 5562180 | &nbsp;&nbsp; 5575073 |
| Preferred Term Securities XIX Ltd., CDO, FLR, 4.93% ((SOFR - 3mo. + 0.26161%) + 0.35%), 12/22/2035 (n) | 86683 | &nbsp;&nbsp; 82346 |
| ReadyCap Commercial Mortgage Trust, 2021-FL7, "C", FLR, 6.633% ((SOFR - 1mo. + 0.11448%) + 2.2%), 11/25/2036 (n) | 1340000 | &nbsp;&nbsp; 1332183 |
| ReadyCap Commercial Mortgage Trust, 2021-FL7, "D", FLR, 7.383% ((SOFR - 1mo. + 0.11448%) + 2.95%), 11/25/2036 (n) | 1575000 | &nbsp;&nbsp; 1573378 |
| Residential Funding Mortgage Securities, Inc., FGIC, 3.985%, 12/25/2035 (d)(q) | 2975 | &nbsp;&nbsp; 47 |
| Rockford Tower CLO 2020-1A, Ltd., "BRR", FLR, 5.819% (SOFR - 3mo. + 1.55%), 1/20/2036 (n) | 3331195 | &nbsp;&nbsp; 3323077 |
| Sammons Financial Group, Inc., FLR, 6.069% (SOFR - 3mo. + 1.8%), 10/21/2034 (n) | 2673048 | &nbsp;&nbsp; 2659488 |
| Santander Drive Auto Receivables Trust, 2025-1, 4.74%, 1/16/2029  | 2384000 | &nbsp;&nbsp; 2393171 |
| Starwood Commercial Mortgage, 2021-FL2, "C", FLR, 6.529% ((SOFR - 1mo. + 0.11448)% + 2.1%), 4/18/2038 (n) | 2027000 | &nbsp;&nbsp; 1998194 |
| Starwood Commercial Mortgage, 2022-FL3, "B", FLR, 6.253% (SOFR - 30 day + 1.95%), 11/15/2038 (n) | 1391000 | &nbsp;&nbsp; 1363516 |
| Starwood Commercial Mortgage, 2022-FL3, "C", FLR, 6.503% (SOFR - 30 day + 2.2%), 11/15/2038 (n) | 2632000 | &nbsp;&nbsp; 2555375 |
| Stellantis Finance US, Inc., 4.63%, 7/20/2027 (n) | 3016393 | &nbsp;&nbsp; 3023644 |
| STORE Master Funding LLC, 2014-1A, "A1", 5.69%, 5/20/2054 (n) | 433392 | &nbsp;&nbsp; 438776 |
| STORE Master Funding LLC, 2014-1A, "A2", 5.7%, 5/20/2054 (n) | 905349 | &nbsp;&nbsp; 929472 |
| UBS Commercial Mortgage Trust, 2017-C8, "A4", 3.983%, 2/15/2051  | 5865766 | &nbsp;&nbsp; 5762249 |
| Venture CLO 43 Ltd., 2021-43A, "BR", FLR, 6.106% (SOFR - 3mo. + 1.85%), 4/15/2034 (n) | 5537477 | &nbsp;&nbsp; 5539454 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued |
| Verus Securitization Trust, 2014-1, "A1", 5.712%, 1/25/2069 (n) | $1312393 | &nbsp;&nbsp; $1314913 |
| Verus Securitization Trust, 2024-8, "A1", 5.364%, 10/25/2069 (n) | 1053640 | &nbsp;&nbsp; 1053007 |
| Voya CLO 2012-4A Ltd., "A2R3", FLR, 5.968% ((SOFR - 3mo. + 0.26161%) + 1.45%), 10/15/2030 (n) | 1957793 | &nbsp;&nbsp; 1958717 |
| Voya CLO 2012-4A Ltd., "BR3", FLR, 6.467% ((SOFR - 3mo. + 0.26161%) + 1.95%), 10/15/2030 (n) | 828265 | &nbsp;&nbsp; 828773 |
| Voya CLO 2012-4A Ltd., "C1R3", FLR, 7.817% ((SOFR - 3mo. + 0.26161%) + 3.3%), 10/15/2030 (n) | 1187823 | &nbsp;&nbsp; 1189466 |
| Wells Fargo Commercial Mortgage Trust, 2016-LC25, "A4", 3.64%, 12/15/2059  | 13071416 | &nbsp;&nbsp; 12857985 |
| Wells Fargo Commercial Mortgage Trust, 2017-C42, "A5", 3.589%, 12/15/2050  | 3970000 | &nbsp;&nbsp; 3855012 |
|  |  | &nbsp;&nbsp; $289469557 |
| Broadcasting – 0.1% | Broadcasting – 0.1% | Broadcasting – 0.1% |
| WMG Acquisition Corp., 3%, 2/15/2031 (n) | $1568000 | &nbsp;&nbsp; $1421855 |
| Brokerage & Asset Managers – 1.3% | Brokerage & Asset Managers – 1.3% | Brokerage & Asset Managers – 1.3% |
| Charles Schwab Corp., 5.853% to 5/19/2033, FLR (SOFR - 1 day + 2.5%) to 5/19/2034  | $2300000 | &nbsp;&nbsp; $2443316 |
| Charles Schwab Corp., 6.136% to 8/24/2033, FLR (SOFR - 1 day + 2.01%) to 8/24/2034  | 2878000 | &nbsp;&nbsp; 3113936 |
| Charles Schwab Corp., 5% to 6/01/2027, FLR (CMT - 5yr. + 3.256%) to 6/01/2170  | 6058000 | &nbsp;&nbsp; 6036651 |
| LPL Holdings, Inc., 6.75%, 11/17/2028  | 1167000 | &nbsp;&nbsp; 1244608 |
| LPL Holdings, Inc., 4%, 3/15/2029 (n) | 4555000 | &nbsp;&nbsp; 4424857 |
| LPL Holdings, Inc., 6%, 5/20/2034  | 1917000 | &nbsp;&nbsp; 1982319 |
|  |  | &nbsp;&nbsp; $19245687 |
| Building – 0.6% | Building – 0.6% | Building – 0.6% |
| Standard Industries, Inc., 4.375%, 7/15/2030 (n) | $5875000 | &nbsp;&nbsp; $5562694 |
| Vulcan Materials Co., 3.5%, 6/01/2030  | 3356000 | &nbsp;&nbsp; 3210662 |
|  |  | &nbsp;&nbsp; $8773356 |
| Business Services – 1.3% | Business Services – 1.3% | Business Services – 1.3% |
| Equinix, Inc., 2.15%, 7/15/2030  | $4789000 | &nbsp;&nbsp; $4261999 |
| Fiserv, Inc., 3.5%, 7/01/2029  | 2280000 | &nbsp;&nbsp; 2196324 |
| Fiserv, Inc., 5.6%, 3/02/2033  | 2183000 | &nbsp;&nbsp; 2263564 |
| Global Payments, Inc., 2.9%, 5/15/2030  | 5153000 | &nbsp;&nbsp; 4737618 |
| Global Payments, Inc., 2.9%, 11/15/2031  | 1508000 | &nbsp;&nbsp; 1333788 |
| Iron Mountain, Inc., 4.5%, 2/15/2031 (n) | 5315000 | &nbsp;&nbsp; 5064081 |
|  |  | &nbsp;&nbsp; $19857374 |
| Cable TV – 1.0% | Cable TV – 1.0% | Cable TV – 1.0% |
| CCO Holdings LLC/CCO Holdings Capital Corp., 4.5%, 8/15/2030 (n) | $6587000 | &nbsp;&nbsp; $6279911 |
| Charter Communications Operating LLC/Charter Communications Operating Capital Corp., 5.25%, 4/01/2053  | 6586000 | &nbsp;&nbsp; 5595414 |
| Time Warner Cable, Inc., 4.5%, 9/15/2042  | 3558000 | &nbsp;&nbsp; 2833884 |
| Time Warner Entertainment Co. LP, 8.375%, 7/15/2033  | 290000 | &nbsp;&nbsp; 337701 |
|  |  | &nbsp;&nbsp; $15046910 |
| Computer Software – 0.5% | Computer Software – 0.5% | Computer Software – 0.5% |
| Dell International LLC/EMC Corp., 5.3%, 10/01/2029  | $6901000 | &nbsp;&nbsp; $7102219 |
| Computer Software - Systems – 0.3% | Computer Software - Systems – 0.3% | Computer Software - Systems – 0.3% |
| SS&C Technologies Holdings, Inc., 5.5%, 9/30/2027 (n) | $4802000 | &nbsp;&nbsp; $4806211 |
| Conglomerates – 1.0% | Conglomerates – 1.0% | Conglomerates – 1.0% |
| Regal Rexnord Corp., 6.05%, 4/15/2028  | $1521000 | &nbsp;&nbsp; $1567365 |
| Regal Rexnord Corp., 6.3%, 2/15/2030  | 4643000 | &nbsp;&nbsp; 4863659 |
| Regal Rexnord Corp., 6.4%, 4/15/2033  | 3600000 | &nbsp;&nbsp; 3800896 |
| Westinghouse Air Brake Technologies Corp., 4.7%, 9/15/2028  | 4993000 | &nbsp;&nbsp; 5021633 |
|  |  | &nbsp;&nbsp; $15253553 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Consumer Products – 0.2% | Consumer Products – 0.2% | Consumer Products – 0.2% |
| Haleon US Capital LLC, 3.625%, 3/24/2032  | $3229000 | &nbsp;&nbsp; $3020989 |
| Consumer Services – 0.2% | Consumer Services – 0.2% | Consumer Services – 0.2% |
| CBRE Group, Inc., 5.95%, 8/15/2034  | $2539000 | &nbsp;&nbsp; $2673104 |
| Electrical Equipment – 0.3% | Electrical Equipment – 0.3% | Electrical Equipment – 0.3% |
| Arrow Electronics, Inc., 2.95%, 2/15/2032  | $4838000 | &nbsp;&nbsp; $4247060 |
| Electronics – 0.4% | Electronics – 0.4% | Electronics – 0.4% |
| Broadcom, Inc., 3.137%, 11/15/2035 (n) | $3219000 | &nbsp;&nbsp; $2715031 |
| Broadcom, Inc., 4.926%, 5/15/2037 (n) | 3219000 | &nbsp;&nbsp; 3124116 |
|  |  | &nbsp;&nbsp; $5839147 |
| Energy - Independent – 0.7% | Energy - Independent – 0.7% | Energy - Independent – 0.7% |
| EQT Corp., 3.9%, 10/01/2027  | $1728000 | &nbsp;&nbsp; $1705094 |
| EQT Corp., 5%, 1/15/2029  | 1294000 | &nbsp;&nbsp; 1304965 |
| EQT Corp., 3.625%, 5/15/2031 (n) | 1506000 | &nbsp;&nbsp; 1395897 |
| Santos Finance Ltd., 6.875%, 9/19/2033 (n) | 3007000 | &nbsp;&nbsp; 3283277 |
| Tengizchevroil Finance Co. International Ltd. (Republic of Kazakhstan), 3.25%, 8/15/2030  | 3294000 | &nbsp;&nbsp; 2930155 |
|  |  | &nbsp;&nbsp; $10619388 |
| Energy - Integrated – 0.1% | Energy - Integrated – 0.1% | Energy - Integrated – 0.1% |
| Eni S.p.A., 5.5%, 5/15/2034 (n) | $1487000 | &nbsp;&nbsp; $1497929 |
| Financial Institutions – 0.8% | Financial Institutions – 0.8% | Financial Institutions – 0.8% |
| AerCap Ireland Capital DAC/AerCap Global Aviation Trust, 6.5%, 7/15/2025  | $3195000 | &nbsp;&nbsp; $3197039 |
| AerCap Ireland Capital DAC/AerCap Global Aviation Trust, 3%, 10/29/2028  | 2329000 | &nbsp;&nbsp; 2218780 |
| AerCap Ireland Capital DAC/AerCap Global Aviation Trust, 3.3%, 1/30/2032  | 1334000 | &nbsp;&nbsp; 1208590 |
| Avolon Holdings Funding Ltd., 2.125%, 2/21/2026 (n) | 2890000 | &nbsp;&nbsp; 2836615 |
| Avolon Holdings Funding Ltd., 4.25%, 4/15/2026 (n) | 1779000 | &nbsp;&nbsp; 1768671 |
| Avolon Holdings Funding Ltd., 2.75%, 2/21/2028 (n) | 497000 | &nbsp;&nbsp; 471645 |
|  |  | &nbsp;&nbsp; $11701340 |
| Food & Beverages – 0.5% | Food & Beverages – 0.5% | Food & Beverages – 0.5% |
| JBS USA Lux S.A./JBS USA Food Co./JBS USA Finance, Inc., 5.5%, 1/15/2030  | $1590000 | &nbsp;&nbsp; $1626430 |
| Performance Food Group Co., 6.125%, 9/15/2032 (n) | 3726000 | &nbsp;&nbsp; 3811452 |
| Post Holdings, Inc., 5.5%, 12/15/2029 (n) | 1441000 | &nbsp;&nbsp; 1434393 |
| Post Holdings, Inc., 4.625%, 4/15/2030 (n) | 1225000 | &nbsp;&nbsp; 1177512 |
| Post Holdings, Inc., 4.5%, 9/15/2031 (n) | 216000 | &nbsp;&nbsp; 200493 |
|  |  | &nbsp;&nbsp; $8250280 |
| Gaming & Lodging – 0.5% | Gaming & Lodging – 0.5% | Gaming & Lodging – 0.5% |
| Hilton Domestic Operating Co., Inc., 5.875%, 3/15/2033 (n) | $3765000 | &nbsp;&nbsp; $3836076 |
| Marriott International, Inc., 3.5%, 10/15/2032  | 3330000 | &nbsp;&nbsp; 3027220 |
|  |  | &nbsp;&nbsp; $6863296 |
| Insurance – 0.8% | Insurance – 0.8% | Insurance – 0.8% |
| Corebridge Financial, Inc., 3.9%, 4/05/2032  | $3293000 | &nbsp;&nbsp; $3090845 |
| Corebridge Financial, Inc., 5.75%, 1/15/2034  | 2801000 | &nbsp;&nbsp; 2910014 |
| Corebridge Financial, Inc., 4.35%, 4/05/2042  | 442000 | &nbsp;&nbsp; 370996 |
| Corebridge Financial, Inc., 4.4%, 4/05/2052  | 1291000 | &nbsp;&nbsp; 1031434 |
| Sammons Financial Group, Inc., 6.875%, 4/15/2034 (n) | 4897000 | &nbsp;&nbsp; 5243129 |
|  |  | &nbsp;&nbsp; $12646418 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Insurance - Health – 0.3% | Insurance - Health – 0.3% | Insurance - Health – 0.3% |
| Humana, Inc., 5.875%, 3/01/2033  | $4131000 | &nbsp;&nbsp; $4269124 |
| Insurance - Property & Casualty – 1.0% | Insurance - Property & Casualty – 1.0% | Insurance - Property & Casualty – 1.0% |
| Fairfax Financial Holdings Ltd., 4.85%, 4/17/2028  | $5692000 | &nbsp;&nbsp; $5741526 |
| Fairfax Financial Holdings Ltd., 3.375%, 3/03/2031  | 1060000 | &nbsp;&nbsp; 983827 |
| Fairfax Financial Holdings Ltd., 5.625%, 8/16/2032  | 2374000 | &nbsp;&nbsp; 2438140 |
| Hub International Ltd., 7.25%, 6/15/2030 (n) | 3479000 | &nbsp;&nbsp; 3635677 |
| Liberty Mutual Group, Inc., 3.951%, 10/15/2050 (n) | 2221000 | &nbsp;&nbsp; 1623832 |
|  |  | &nbsp;&nbsp; $14423002 |
| International Market Quasi-Sovereign – 0.1% | International Market Quasi-Sovereign – 0.1% | International Market Quasi-Sovereign – 0.1% |
| Electricite de France S.A., 6.9%, 5/23/2053 (n) | $1704000 | &nbsp;&nbsp; $1818326 |
| Machinery & Tools – 0.5% | Machinery & Tools – 0.5% | Machinery & Tools – 0.5% |
| Ashtead Capital, Inc., 5.55%, 5/30/2033 (n) | $4843000 | &nbsp;&nbsp; $4891075 |
| Ashtead Capital, Inc., 5.8%, 4/15/2034 (n) | 1161000 | &nbsp;&nbsp; 1188231 |
| CNH Industrial N.V., 3.85%, 11/15/2027  | 1328000 | &nbsp;&nbsp; 1314379 |
|  |  | &nbsp;&nbsp; $7393685 |
| Major Banks – 7.8% | Major Banks – 7.8% | Major Banks – 7.8% |
| Bank of America Corp., 2.496% to 2/13/2030, FLR ((SOFR - 3mo. + 0.26161%) + 0.99%) to 2/13/2031  | $4007000 | &nbsp;&nbsp; $3659840 |
| Bank of America Corp., 2.572% to 10/20/2031, FLR (SOFR - 1 day + 1.21%) to 10/20/2032  | 10928000 | &nbsp;&nbsp; 9631514 |
| Bank of America Corp., 5.875% to 3/15/2028, FLR ((SOFR - 3mo. + 0.26161%) + 2.931%) to 9/15/2171  | 3924000 | &nbsp;&nbsp; 3991363 |
| Barclays PLC, 4.972% to 5/16/2028, FLR (LIBOR - 3mo. + 1.902%) to 5/16/2029  | 3191000 | &nbsp;&nbsp; 3224360 |
| Barclays PLC, 2.894% to 11/24/2031, FLR (CMT - 1yr. + 1.3%) to 11/24/2032  | 3776000 | &nbsp;&nbsp; 3341894 |
| Capital One Financial Corp., 5.817% to 2/01/2033, FLR (SOFR - 1 day + 2.6%) to 2/01/2034  | 2325000 | &nbsp;&nbsp; 2398516 |
| Capital One Financial Corp., 6.377% to 6/08/2033, FLR (SOFR - 1 day + 2.86%) to 6/08/2034  | 3594000 | &nbsp;&nbsp; 3826185 |
| Capital One Financial Corp., 6.051% to 2/01/2034, FLR (SOFR - 1 day + 2.26%) to 2/01/2035  | 2981000 | &nbsp;&nbsp; 3107344 |
| Deutsche Bank AG, 2.311% to 11/16/2026, FLR (SOFR - 1 day + 1.219%) to 11/16/2027  | 5055000 | &nbsp;&nbsp; 4904727 |
| Deutsche Bank AG, 6.72% to 1/18/2028, FLR (SOFR - 1 day + 3.18%) to 1/18/2029  | 5453000 | &nbsp;&nbsp; 5728227 |
| Discover Financial Services, 6.7%, 11/29/2032  | 7435000 | &nbsp;&nbsp; 8118396 |
| Goldman Sachs Group, Inc., 2.6%, 2/07/2030  | 6000000 | &nbsp;&nbsp; 5545049 |
| HSBC Holdings PLC, 4.7% to 9/09/2031, FLR (CMT - 1yr. + 3.25%) to 9/09/2169  | 6176000 | &nbsp;&nbsp; 5598230 |
| HSBC Holdings PLC, 4% to 9/09/2026, FLR (CMT - 1yr. + 3.222%) to 9/09/2170  | 2447000 | &nbsp;&nbsp; 2405630 |
| JPMorgan Chase & Co., 3.509% to 1/23/2028, FLR ((SOFR - 3mo. + 0.26161%) + 0.945%) to 1/23/2029  | 2290000 | &nbsp;&nbsp; 2243153 |
| JPMorgan Chase & Co., 4.005% to 4/23/2028, FLR ((SOFR - 3mo. + 0.26161%) + 1.12%) to 4/23/2029  | 5871000 | &nbsp;&nbsp; 5819351 |
| JPMorgan Chase & Co., 4.203% to 7/23/2028, FLR ((SOFR - 3mo. + 0.26161%) + 1.26%) to 7/23/2029  | 2576000 | &nbsp;&nbsp; 2565118 |
| JPMorgan Chase & Co., 2.956% to 5/13/2030, FLR (SOFR - 1 day + 2.515%) to 5/13/2031  | 4435000 | &nbsp;&nbsp; 4101045 |
| JPMorgan Chase & Co., 2.545% to 11/08/2031, FLR (SOFR - 1 day + 1.18%) to 11/08/2032  | 3363000 | &nbsp;&nbsp; 2960597 |
| Lloyds Bank PLC, 3.75%, 1/11/2027  | 2765000 | &nbsp;&nbsp; 2741019 |
| Morgan Stanley, 5.449% to 7/20/2028, FLR (SOFR - 1 day + 1.63%) to 7/20/2029  | 1239000 | &nbsp;&nbsp; 1274251 |
| Morgan Stanley, 2.511% to 10/20/2031, FLR (SOFR - 1 day + 1.2%) to 10/20/2032  | 6985000 | &nbsp;&nbsp; 6116835 |
| Morgan Stanley, 5.424% to 7/21/2033, FLR (SOFR - 1 day + 1.88%) to 7/21/2034  | 2940000 | &nbsp;&nbsp; 3011743 |
| NatWest Group PLC, 6.016% to 3/02/2033, FLR (CMT - 1yr. + 2.1%) to 3/02/2034  | 769000 | &nbsp;&nbsp; 813668 |
| Sumitomo Mitsui Financial Group, Inc., 2.13%, 7/08/2030  | 5402000 | &nbsp;&nbsp; 4826725 |
| UBS Group AG, 4.375% to 2/10/2031, FLR (CMT - 1yr. + 3.313%) to 8/10/2171 (n) | 7084000 | &nbsp;&nbsp; 6261031 |
| UBS Group Funding (Jersey) Ltd., 4.125%, 9/24/2025 (n) | 4524000 | &nbsp;&nbsp; 4516477 |
| Wells Fargo & Co., 2.572% to 2/11/2030, FLR ((SOFR - 3mo. + 0.26161%) + 1%) to 2/11/2031  | 4514000 | &nbsp;&nbsp; 4135350 |
|  |  | &nbsp;&nbsp; $116867638 |
| Medical & Health Technology & Services – 2.0% | Medical & Health Technology & Services – 2.0% | Medical & Health Technology & Services – 2.0% |
| Adventist Health System/West, 5.43%, 3/01/2032  | $4476000 | &nbsp;&nbsp; $4495430 |
| Alcon Finance Corp., 2.75%, 9/23/2026 (n) | 593000 | &nbsp;&nbsp; 580122 |
| Alcon Finance Corp., 2.6%, 5/27/2030 (n) | 1096000 | &nbsp;&nbsp; 1001958 |
| Alcon Finance Corp., 5.375%, 12/06/2032 (n) | 1318000 | &nbsp;&nbsp; 1360657 |
| HCA, Inc., 4.125%, 6/15/2029  | 3255000 | &nbsp;&nbsp; 3198132 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Medical & Health Technology & Services – continued | Medical & Health Technology & Services – continued | Medical & Health Technology & Services – continued |
| HCA, Inc., 4.375%, 3/15/2042  | $3251000 | &nbsp;&nbsp; $2708692 |
| ICON Investments Six DAC, 6%, 5/08/2034  | 2657000 | &nbsp;&nbsp; 2715399 |
| Marin General Hospital, 7.242%, 8/01/2045  | 2243000 | &nbsp;&nbsp; 2526527 |
| Northwell Healthcare, Inc., 3.979%, 11/01/2046  | 1503000 | &nbsp;&nbsp; 1155426 |
| ProMedica Toledo Hospital, "B", 5.325%, 11/15/2028  | 7120000 | &nbsp;&nbsp; 7097738 |
| ProMedica Toledo Hospital, "B", AGM, 5.75%, 11/15/2038  | 2562000 | &nbsp;&nbsp; 2558990 |
|  |  | &nbsp;&nbsp; $29399071 |
| Medical Equipment – 0.2% | Medical Equipment – 0.2% | Medical Equipment – 0.2% |
| Medline Borrower LP/Medline Co-Issuer, Inc., 6.25%, 4/01/2029 (n) | $2656000 | &nbsp;&nbsp; $2728466 |
| Metals & Mining – 1.4% | Metals & Mining – 1.4% | Metals & Mining – 1.4% |
| Anglo American Capital PLC, 3.875%, 3/16/2029 (n) | $3434000 | &nbsp;&nbsp; $3353958 |
| Anglo American Capital PLC, 2.875%, 3/17/2031 (n) | 2927000 | &nbsp;&nbsp; 2642101 |
| Anglo American Capital PLC, 4.75%, 3/16/2052 (n) | 4511000 | &nbsp;&nbsp; 3760985 |
| FMG Resources Ltd., 4.375%, 4/01/2031 (n) | 3922000 | &nbsp;&nbsp; 3664722 |
| Glencore Funding LLC, 2.85%, 4/27/2031 (n) | 4010000 | &nbsp;&nbsp; 3615379 |
| Novelis, Inc., 3.875%, 8/15/2031 (n) | 3638000 | &nbsp;&nbsp; 3268980 |
|  |  | &nbsp;&nbsp; $20306125 |
| Midstream – 2.6% | Midstream – 2.6% | Midstream – 2.6% |
| Cheniere Corpus Christi Holdings LLC, 2.742%, 12/31/2039  | $1939000 | &nbsp;&nbsp; $1578123 |
| Cheniere Energy Partners LP, 5.55%, 10/30/2035 (n)(w) | 4963000 | &nbsp;&nbsp; 5002020 |
| Enbridge, Inc., 5.7%, 3/08/2033  | 1601000 | &nbsp;&nbsp; 1659890 |
| Energy Transfer LP, 5.55%, 2/15/2028  | 1261000 | &nbsp;&nbsp; 1297372 |
| Energy Transfer LP, 5.75%, 2/15/2033  | 3863000 | &nbsp;&nbsp; 4009770 |
| Kinder Morgan (Delaware), Inc., 7.75%, 1/15/2032  | 3350000 | &nbsp;&nbsp; 3866971 |
| Kinder Morgan Energy Partners LP, 6.375%, 3/01/2041  | 2040000 | &nbsp;&nbsp; 2107509 |
| MPLX LP, 4.95%, 3/14/2052  | 5874000 | &nbsp;&nbsp; 4862972 |
| Plains All American Pipeline LP, 3.55%, 12/15/2029  | 2839000 | &nbsp;&nbsp; 2713683 |
| Targa Resources Corp., 4.2%, 2/01/2033  | 930000 | &nbsp;&nbsp; 871410 |
| Targa Resources Corp., 6.125%, 3/15/2033  | 4345000 | &nbsp;&nbsp; 4579213 |
| Targa Resources Corp., 4.95%, 4/15/2052  | 1533000 | &nbsp;&nbsp; 1278862 |
| Venture Global Calcasieu Pass LLC, 6.25%, 1/15/2030 (n) | 4349000 | &nbsp;&nbsp; 4485450 |
|  |  | &nbsp;&nbsp; $38313245 |
| Mortgage-Backed – 17.8% | Mortgage-Backed – 17.8% |  |
| Fannie Mae, 3.5%, 3/01/2026 - 7/01/2046  | $5191918 | &nbsp;&nbsp; $4864552 |
| Fannie Mae, 3.95%, 1/01/2027  | 294520 | &nbsp;&nbsp; 293577 |
| Fannie Mae, 3%, 11/01/2028 - 8/01/2047  | 4433159 | &nbsp;&nbsp; 4037038 |
| Fannie Mae, 2.5%, 11/01/2031 - 11/01/2046  | 632038 | &nbsp;&nbsp; 546106 |
| Fannie Mae, 6.5%, 7/01/2032 - 1/01/2033  | 1409 | &nbsp;&nbsp; 1461 |
| Fannie Mae, 3%, 2/25/2033 (i) | 227638 | &nbsp;&nbsp; 15864 |
| Fannie Mae, 5.5%, 5/01/2033 - 12/01/2038  | 2476486 | &nbsp;&nbsp; 2547421 |
| Fannie Mae, 5%, 11/01/2033 - 3/01/2042  | 1895835 | &nbsp;&nbsp; 1921376 |
| Fannie Mae, 4.5%, 3/01/2034 - 6/01/2044  | 6252135 | &nbsp;&nbsp; 6220482 |
| Fannie Mae, 6%, 10/01/2035 - 3/01/2039  | 668482 | &nbsp;&nbsp; 698045 |
| Fannie Mae, 4%, 12/01/2039 - 1/01/2047  | 10781344 | &nbsp;&nbsp; 10403754 |
| Fannie Mae, 3.25%, 5/25/2040  | 84083 | &nbsp;&nbsp; 80205 |
| Fannie Mae, 2%, 4/25/2046  | 181762 | &nbsp;&nbsp; 168867 |
| Fannie Mae, 4%, 7/25/2046 (i) | 308893 | &nbsp;&nbsp; 57231 |
| Fannie Mae, 3.5%, 12/01/2046 (f) | 1138062 | &nbsp;&nbsp; 1052439 |
| Fannie Mae, UMBS, 3.5%, 1/01/2027  | 5811 | &nbsp;&nbsp; 5764 |
| Fannie Mae, UMBS, 2.5%, 4/01/2036 - 6/01/2052  | 32861519 | &nbsp;&nbsp; 27734504 |
| Fannie Mae, UMBS, 2%, 1/01/2037 - 3/01/2052  | 29702100 | &nbsp;&nbsp; 24144429 |
| Fannie Mae, UMBS, 3%, 4/01/2037 - 8/01/2052  | 13419376 | &nbsp;&nbsp; 11755953 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Mortgage-Backed – continued | Mortgage-Backed – continued |  |
| Fannie Mae, UMBS, 1.5%, 2/01/2042  | $151888 | &nbsp;&nbsp; $124886 |
| Fannie Mae, UMBS, 6.5%, 4/01/2043 - 10/01/2053  | 576596 | &nbsp;&nbsp; 596538 |
| Fannie Mae, UMBS, 4.5%, 9/01/2052  | 611213 | &nbsp;&nbsp; 588862 |
| Fannie Mae, UMBS, 5%, 12/01/2052 - 3/01/2053  | 5443576 | &nbsp;&nbsp; 5355732 |
| Fannie Mae, UMBS, 6%, 12/01/2052 - 12/01/2053  | 1444168 | &nbsp;&nbsp; 1469970 |
| Fannie Mae, UMBS, 5.5%, 4/01/2053 - 11/01/2053  | 3532934 | &nbsp;&nbsp; 3535889 |
| Federal Home Loan Bank, 5%, 7/01/2035  | 528447 | &nbsp;&nbsp; 536290 |
| Freddie Mac, 4%, 7/01/2025 - 4/01/2044  | 1031249 | &nbsp;&nbsp; 990158 |
| Freddie Mac, 4.5%, 7/01/2025 - 5/01/2042  | 1574199 | &nbsp;&nbsp; 1568337 |
| Freddie Mac, 3.3%, 10/25/2026  | 2958000 | &nbsp;&nbsp; 2919857 |
| Freddie Mac, 3%, 6/15/2028 - 2/25/2059  | 7537542 | &nbsp;&nbsp; 6791293 |
| Freddie Mac, 1.214%, 7/25/2029 (i) | 3947970 | &nbsp;&nbsp; 146694 |
| Freddie Mac, 1.261%, 8/25/2029 (i) | 6852594 | &nbsp;&nbsp; 272913 |
| Freddie Mac, 1.954%, 4/25/2030 (i) | 1901414 | &nbsp;&nbsp; 145279 |
| Freddie Mac, 5.5%, 5/01/2034 - 1/01/2038  | 119078 | &nbsp;&nbsp; 122362 |
| Freddie Mac, 6%, 8/01/2034 - 7/01/2038  | 36886 | &nbsp;&nbsp; 38383 |
| Freddie Mac, 5%, 11/01/2035 - 7/01/2041  | 583930 | &nbsp;&nbsp; 592168 |
| Freddie Mac, 5.5%, 2/15/2036 (i) | 52803 | &nbsp;&nbsp; 8430 |
| Freddie Mac, 3.5%, 11/01/2037 - 10/25/2058  | 8667444 | &nbsp;&nbsp; 8095052 |
| Freddie Mac, 4.5%, 12/15/2040 (i) | 21234 | &nbsp;&nbsp; 1973 |
| Freddie Mac, 4%, 8/15/2044 (i) | 50756 | &nbsp;&nbsp; 4547 |
| Freddie Mac, UMBS, 3%, 10/01/2037 - 6/01/2052  | 3110759 | &nbsp;&nbsp; 2740055 |
| Freddie Mac, UMBS, 2%, 2/01/2042 - 5/01/2052  | 26634552 | &nbsp;&nbsp; 21275954 |
| Freddie Mac, UMBS, 3.5%, 12/01/2046 - 7/01/2054  | 1194111 | &nbsp;&nbsp; 1084853 |
| Freddie Mac, UMBS, 2.5%, 7/01/2051 - 9/01/2052  | 9844688 | &nbsp;&nbsp; 8211278 |
| Freddie Mac, UMBS, 5%, 8/01/2052 - 10/01/2052  | 716507 | &nbsp;&nbsp; 704647 |
| Freddie Mac, UMBS, 4.5%, 10/01/2052  | 1407639 | &nbsp;&nbsp; 1348998 |
| Freddie Mac, UMBS, 5.5%, 4/01/2053 - 10/01/2054  | 3269011 | &nbsp;&nbsp; 3276585 |
| Freddie Mac, UMBS, 6%, 6/01/2054 - 2/01/2055  | 5330058 | &nbsp;&nbsp; 5443369 |
| Ginnie Mae, 5.5%, 5/15/2033 - 1/20/2055  | 6180929 | &nbsp;&nbsp; 6225680 |
| Ginnie Mae, 6%, 1/20/2036 - 1/15/2039  | 65861 | &nbsp;&nbsp; 68657 |
| Ginnie Mae, 4.5%, 4/15/2039 - 12/20/2052  | 10959972 | &nbsp;&nbsp; 10656784 |
| Ginnie Mae, 4%, 10/20/2040 - 10/20/2052  | 7131410 | &nbsp;&nbsp; 6693273 |
| Ginnie Mae, 3.5%, 11/15/2040 - 9/20/2053  | 8520466 | &nbsp;&nbsp; 7840950 |
| Ginnie Mae, 3%, 11/20/2044 - 10/20/2052  | 12782511 | &nbsp;&nbsp; 11382950 |
| Ginnie Mae, 2.5%, 8/20/2051 - 6/20/2052  | 13844547 | &nbsp;&nbsp; 11768056 |
| Ginnie Mae, 2%, 1/20/2052 - 3/20/2052  | 11613077 | &nbsp;&nbsp; 9459748 |
| Ginnie Mae, 5%, 1/20/2053 - 5/20/2053  | 9030015 | &nbsp;&nbsp; 8906322 |
| Ginnie Mae, 6.5%, 7/20/2054  | 525023 | &nbsp;&nbsp; 539715 |
| UMBS, TBA, 2%, 7/01/2040 - 8/01/2055  | 12075000 | &nbsp;&nbsp; 10448958 |
| UMBS, TBA, 2.5%, 7/25/2040  | 2700000 | &nbsp;&nbsp; 2520350 |
| UMBS, TBA, 3%, 7/01/2055  | 500000 | &nbsp;&nbsp; 432570 |
| UMBS, TBA, 6.5%, 7/01/2055  | 3375000 | &nbsp;&nbsp; 3484609 |
|  |  | &nbsp;&nbsp; $264969042 |
| Municipals – 1.8% | Municipals – 1.8% | Municipals – 1.8% |
| Berks County, PA, Municipal Authority Rev. (Tower Health Project), "A-4", 7%, 6/30/2039  | $4348000 | &nbsp;&nbsp; $3814458 |
| Berks County, PA, Municipal Authority Rev. (Tower Health Project), Convertible Capital Appreciation, Taxable, "B-2", 0% to <br> 11/15/2029, 8% to 6/30/2044 <br>| 2286000 | &nbsp;&nbsp; 1298865 |
| Bridgeview, IL, Stadium & Redevelopment Projects, Taxable, AAC, 5.06%, 12/01/2025  | 215000 | &nbsp;&nbsp; 214595 |
| Bridgeview, IL, Stadium & Redevelopment Projects, Taxable, AAC, 5.14%, 12/01/2036  | 8850000 | &nbsp;&nbsp; 8103179 |
| Escambia County, FL, Health Facilities Authority Rev., Taxable (Baptist Health Care Corp.), "B", AGM, 3.607%, 8/15/2040  | 1295000 | &nbsp;&nbsp; 1032936 |
| Oklahoma Development Finance Authority, Health System Rev., Taxable (OU Medicine Project), "C", 5.45%, 8/15/2028  | 3770000 | &nbsp;&nbsp; 3668091 |
| Philadelphia, PA, School District, Taxable, "B", AGM, 6.615%, 6/01/2030  | 3250000 | &nbsp;&nbsp; 3425085 |
| State of Florida, Taxable, "A", 2.154%, 7/01/2030  | 5223000 | &nbsp;&nbsp; 4673283 |
|  |  | &nbsp;&nbsp; $26230492 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Natural Gas - Distribution – 0.8% | Natural Gas - Distribution – 0.8% | Natural Gas - Distribution – 0.8% |
| Boston Gas Co., 3.15%, 8/01/2027 (n) | $9122000 | &nbsp;&nbsp; $8880334 |
| NiSource, Inc., 3.6%, 5/01/2030  | 2622000 | &nbsp;&nbsp; 2514960 |
|  |  | &nbsp;&nbsp; $11395294 |
| Natural Gas - Pipeline – 0.0% | Natural Gas - Pipeline – 0.0% | Natural Gas - Pipeline – 0.0% |
| APA Infrastructure Ltd., 5.125%, 9/16/2034 (n) | $391000 | &nbsp;&nbsp; $383444 |
| Oils – 0.2% | Oils – 0.2% | Oils – 0.2% |
| Marathon Petroleum Corp., 5.85%, 12/15/2045  | $2507000 | &nbsp;&nbsp; $2342949 |
| Other Banks & Diversified Financials – 0.9% | Other Banks & Diversified Financials – 0.9% | Other Banks & Diversified Financials – 0.9% |
| Macquarie Bank Ltd. of London, 6.125% to 3/08/2027, FLR (Swap Rate - 5yr. + 4.332%) to 12/31/2165 (n) | $4694000 | &nbsp;&nbsp; $4715902 |
| Macquarie Group Ltd., 4.442% to 6/21/2032, FLR (SOFR - 1 day + 2.405%) to 6/21/2033 (n) | 8978000 | &nbsp;&nbsp; 8585595 |
|  |  | &nbsp;&nbsp; $13301497 |
| Real Estate - Office – 0.7% | Real Estate - Office – 0.7% | Real Estate - Office – 0.7% |
| Boston Properties LP, REIT, 2.55%, 4/01/2032  | $7238000 | &nbsp;&nbsp; $6106092 |
| Boston Properties LP, REIT, 6.5%, 1/15/2034  | 1899000 | &nbsp;&nbsp; 2033041 |
| Boston Properties LP, REIT, 5.75%, 1/15/2035  | 2601000 | &nbsp;&nbsp; 2617687 |
|  |  | &nbsp;&nbsp; $10756820 |
| Real Estate - Retail – 0.3% | Real Estate - Retail – 0.3% | Real Estate - Retail – 0.3% |
| Brixmor Operating Partnership LP, 5.75%, 2/15/2035  | $4895000 | &nbsp;&nbsp; $5029705 |
| Restaurants – 0.2% | Restaurants – 0.2% | Restaurants – 0.2% |
| 1011778 B.C. ULC/New Red Finance, Inc., 6.125%, 6/15/2029 (n) | $2656000 | &nbsp;&nbsp; $2723925 |
| Retailers – 0.3% | Retailers – 0.3% | Retailers – 0.3% |
| Penske Automotive Group Co., 3.75%, 6/15/2029  | $5509000 | &nbsp;&nbsp; $5225730 |
| Specialty Chemicals – 0.1% | Specialty Chemicals – 0.1% | Specialty Chemicals – 0.1% |
| International Flavors & Fragrances, Inc., 2.3%, 11/01/2030 (n) | $2330000 | &nbsp;&nbsp; $2059135 |
| Specialty Stores – 0.2% | Specialty Stores – 0.2% | Specialty Stores – 0.2% |
| DICK'S Sporting Goods, 3.15%, 1/15/2032  | $3801000 | &nbsp;&nbsp; $3407231 |
| Telecommunications - Wireless – 1.2% | Telecommunications - Wireless – 1.2% | Telecommunications - Wireless – 1.2% |
| Rogers Communications, Inc., 4.5%, 3/15/2042  | $6129000 | &nbsp;&nbsp; $5222650 |
| Rogers Communications, Inc., 4.55%, 3/15/2052  | 6129000 | &nbsp;&nbsp; 4990781 |
| SBA Communications Corp., 3.125%, 2/01/2029  | 4025000 | &nbsp;&nbsp; 3801523 |
| T-Mobile USA, Inc., 2.55%, 2/15/2031  | 1939000 | &nbsp;&nbsp; 1735845 |
| T-Mobile USA, Inc., 4.375%, 4/15/2040  | 635000 | &nbsp;&nbsp; 562666 |
| Vodafone Group PLC, 5.625%, 2/10/2053  | 1337000 | &nbsp;&nbsp; 1261394 |
|  |  | &nbsp;&nbsp; $17574859 |
| Tobacco – 1.2% | Tobacco – 1.2% | Tobacco – 1.2% |
| B.A.T. Capital Corp., 4.742%, 3/16/2032  | $5611000 | &nbsp;&nbsp; $5578433 |
| B.A.T. International Finance PLC, 4.448%, 3/16/2028  | 4936000 | &nbsp;&nbsp; 4943909 |
| Philip Morris International, Inc., 5.125%, 11/17/2027  | 2140000 | &nbsp;&nbsp; 2182808 |
| Philip Morris International, Inc., 5.625%, 11/17/2029  | 922000 | &nbsp;&nbsp; 968133 |
| Philip Morris International, Inc., 5.125%, 2/15/2030  | 3757000 | &nbsp;&nbsp; 3865300 |
|  |  | &nbsp;&nbsp; $17538583 |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Transportation - Services – 0.8% | Transportation - Services – 0.8% | Transportation - Services – 0.8% |
| ERAC USA Finance LLC, 7%, 10/15/2037 (n) | $1983000 | &nbsp;&nbsp; $2275653 |
| Toll Road Investors Partnership II LP, Capital Appreciation, NPFG, 0%, 2/15/2026 (n) | 2145000 | &nbsp;&nbsp; 2060988 |
| Toll Road Investors Partnership II LP, Capital Appreciation, NPFG, 0%, 2/15/2029 (n) | 6221000 | &nbsp;&nbsp; 4715989 |
| Toll Road Investors Partnership II LP, Capital Appreciation, NPFG, 0%, 2/15/2031 (n) | 2145000 | &nbsp;&nbsp; 1451530 |
| Toll Road Investors Partnership II LP, Capital Appreciation, NPFG, 0%, 2/15/2043 (n) | 3078114 | &nbsp;&nbsp; 1028398 |
|  |  | &nbsp;&nbsp; $11532558 |
| U.S. Government Agencies and Equivalents – 0.6% | U.S. Government Agencies and Equivalents – 0.6% | U.S. Government Agencies and Equivalents – 0.6% |
| Small Business Administration, 4.43%, 5/01/2029  | $41305 | &nbsp;&nbsp; $41318 |
| Small Business Administration, 3.21%, 9/01/2030  | 878711 | &nbsp;&nbsp; 853693 |
| Small Business Administration, 3.25%, 11/01/2030  | 87870 | &nbsp;&nbsp; 85560 |
| Small Business Administration, 2.85%, 9/01/2031  | 189488 | &nbsp;&nbsp; 181285 |
| Small Business Administration, 2.37%, 8/01/2032  | 142566 | &nbsp;&nbsp; 134964 |
| Small Business Administration, 2.13%, 1/01/2033  | 733529 | &nbsp;&nbsp; 684764 |
| Small Business Administration, 2.21%, 2/01/2033  | 182579 | &nbsp;&nbsp; 171356 |
| Small Business Administration, 2.22%, 3/01/2033  | 565664 | &nbsp;&nbsp; 529333 |
| Small Business Administration, 2.08%, 4/01/2033  | 1056429 | &nbsp;&nbsp; 983870 |
| Small Business Administration, 2.45%, 6/01/2033  | 1019728 | &nbsp;&nbsp; 960355 |
| Small Business Administration, 3.15%, 7/01/2033  | 1462984 | &nbsp;&nbsp; 1406248 |
| Small Business Administration, 3.16%, 8/01/2033  | 1691981 | &nbsp;&nbsp; 1627847 |
| Small Business Administration, 3.62%, 9/01/2033  | 1312849 | &nbsp;&nbsp; 1277417 |
|  |  | &nbsp;&nbsp; $8938010 |
| U.S. Treasury Obligations – 22.4% | U.S. Treasury Obligations – 22.4% | U.S. Treasury Obligations – 22.4% |
| U.S. Treasury Bonds, 1.375%, 11/15/2040 (f) | $30300000 | &nbsp;&nbsp; $19303230 |
| U.S. Treasury Bonds, 1.75%, 8/15/2041  | 9700000 | &nbsp;&nbsp; 6439891 |
| U.S. Treasury Bonds, 2.375%, 2/15/2042  | 12900000 | &nbsp;&nbsp; 9384750 |
| U.S. Treasury Bonds, 4%, 11/15/2042  | 17580000 | &nbsp;&nbsp; 16038316 |
| U.S. Treasury Bonds, 4.375%, 8/15/2043  | 9600000 | &nbsp;&nbsp; 9150375 |
| U.S. Treasury Bonds, 4.75%, 11/15/2043  | 30400000 | &nbsp;&nbsp; 30367937 |
| U.S. Treasury Bonds, 4.5%, 2/15/2044  | 33900000 | &nbsp;&nbsp; 32755875 |
| U.S. Treasury Bonds, 4.25%, 2/15/2054  | 14500000 | &nbsp;&nbsp; 13226719 |
| U.S. Treasury Bonds, 4.5%, 11/15/2054  | 2300000 | &nbsp;&nbsp; 2191828 |
| U.S. Treasury Notes, 4.125%, 2/15/2027  | 46800000 | &nbsp;&nbsp; 47024860 |
| U.S. Treasury Notes, 2.5%, 3/31/2027  | 17600000 | &nbsp;&nbsp; 17223937 |
| U.S. Treasury Notes, 4.125%, 7/31/2028  | 70400000 | &nbsp;&nbsp; 71249750 |
| U.S. Treasury Notes, 4.25%, 6/30/2029  | 11500000 | &nbsp;&nbsp; 11713828 |
| U.S. Treasury Notes, 4%, 3/31/2030  | 20000000 | &nbsp;&nbsp; 20185938 |
| U.S. Treasury Notes, 4.25%, 11/15/2034  | 27350000 | &nbsp;&nbsp; 27439742 |
|  |  | &nbsp;&nbsp; $333696976 |
| Utilities - Electric Power – 1.4% | Utilities - Electric Power – 1.4% | Utilities - Electric Power – 1.4% |
| American Electric Power Co., Inc., 5.95%, 11/01/2032  | $2985000 | &nbsp;&nbsp; $3164415 |
| Calpine Corp., 3.75%, 3/01/2031 (n) | 3680000 | &nbsp;&nbsp; 3491099 |
| Enel Finance International N.V., 7.5%, 10/14/2032 (n) | 746000 | &nbsp;&nbsp; 850459 |
| Jersey Central Power & Light Co., 2.75%, 3/01/2032 (n) | 5303000 | &nbsp;&nbsp; 4648839 |
| Pacific Gas & Electric Co., 3%, 6/15/2028  | 2630000 | &nbsp;&nbsp; 2497711 |
| Pacific Gas & Electric Co., 3.3%, 8/01/2040  | 8840000 | &nbsp;&nbsp; 6324101 |
|  |  | &nbsp;&nbsp; $20976624 |
| **Total Bonds (Identified Cost, $1,517,994,372)** |  | &nbsp;&nbsp; **$1460866433** |

---

------

MFS Total Return Bond Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Mutual Funds (h) – 1.9% | Mutual Funds (h) – 1.9% | Mutual Funds (h) – 1.9% |
| Money Market Funds – 1.9% | Money Market Funds – 1.9% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $27,918,832) | 27919307 | &nbsp;&nbsp; $27922099 |
| Other Assets, Less Liabilities – (0.1)% |  | &nbsp;&nbsp; (1257470) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$1487531062** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(d) In default.

&nbsp;&nbsp;&nbsp;&nbsp;(f) All or a portion of the security has been segregated as collateral for open futures
 contracts.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $27,922,099 and $1,460,866,433, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(i) Interest only security for which the fund receives interest on notional principal
 (Par amount). Par amount shown is the notional principal and does not reflect the cost of the security.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933.
 These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers.
 At period end, the aggregate value of these securities was $403,335,622, representing 27.1% of net assets.

&nbsp;&nbsp;&nbsp;&nbsp;(q) Interest received was less than stated coupon rate.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

&nbsp;&nbsp;&nbsp;&nbsp;(w) When-issued security.

---

| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| AAC | Ambac Assurance Corp. |
| AGM | Assured Guaranty Municipal |
| CDO | Collateralized Debt Obligation |
| CLO | Collateralized Loan Obligation |
| CMT | Constant Maturity Treasury |
| FGIC | Financial Guaranty Insurance Co. |
| FLR | Floating Rate. Interest rate resets periodically based on the parenthetically disclosed reference rate plus a spread (if any). The period-end rate <br> reported may not be the current rate. All reference rates are USD unless otherwise noted.<br>|
| LIBOR | London Interbank Offered Rate |
| NPFG | National Public Finance Guarantee Corp. |
| REIT | Real Estate Investment Trust |
| SOFR | Secured Overnight Financing Rate |
| TBA | To Be Announced |
| UMBS | Uniform Mortgage-Backed Security |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** |
| **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** |
| **Description** | &nbsp;&nbsp; **Long/** <br>**Short**<br>| **Currency** | **Contracts** | &nbsp;&nbsp; **Notional** <br>**Amount**<br>| &nbsp;&nbsp;&nbsp; **Expiration** <br>**Date**<br>| &nbsp;&nbsp; **Value/Unrealized** <br>**Appreciation** <br>&nbsp;&nbsp;&nbsp;&nbsp;**(Depreciation)**<br>|
| **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** |
| ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** |  |  |
| U.S. Treasury Note 2 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 154 | &nbsp;&nbsp;&nbsp; $32035609 | September – 2025 | &nbsp;&nbsp;&nbsp; $136605 |
| U.S. Treasury Note 5 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 382 | &nbsp;&nbsp;&nbsp; 41638000 | September – 2025 | &nbsp;&nbsp;&nbsp; 389260 |
| U.S. Treasury Ultra Bond 30 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 655 | &nbsp;&nbsp;&nbsp; 78026875 | September – 2025 | &nbsp;&nbsp;&nbsp; 3250310 |
|  |  |  |  |  |  | &nbsp;&nbsp;&nbsp; $3776175 |

---

At June 30, 2025, the fund had liquid securities with an aggregate value of $4,622,054 to cover any collateral or margin obligations for certain derivative contracts.

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $1,517,994,372) | &nbsp;&nbsp; $1460866433 |
| Investments in affiliated issuers, at value (identified cost, $27,918,832) | &nbsp;&nbsp; 27922099 |
| Receivables for |  |
| Net daily variation margin on open futures contracts | &nbsp;&nbsp; 939359 |
| TBA sale commitments | &nbsp;&nbsp; 1884233 |
| Fund shares sold | &nbsp;&nbsp; 6964873 |
| Interest | &nbsp;&nbsp; 13156038 |
| Other assets | &nbsp;&nbsp; 1731 |
| Total assets | &nbsp;&nbsp; $1511734766 |
| **Liabilities** |  |
| Payable to custodian | &nbsp;&nbsp; $97 |
| Payables for |  |
| When-issued investments purchased | &nbsp;&nbsp; 4956746 |
| TBA purchase commitments | &nbsp;&nbsp; 18571793 |
| Fund shares reacquired | &nbsp;&nbsp; 428800 |
| Payable to affiliates |  |
| Investment adviser | &nbsp;&nbsp; 78778 |
| Administrative services fee | &nbsp;&nbsp; 2170 |
| Shareholder servicing costs | &nbsp;&nbsp; 658 |
| Distribution and/or service fees | &nbsp;&nbsp; 19751 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 5192 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 139719 |
| Total liabilities | &nbsp;&nbsp; $24203704 |
| Net assets | &nbsp;&nbsp; $1487531062 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $1621024686 |
| Total distributable earnings (loss) | &nbsp;&nbsp; (133493624)<br>|
| Net assets | &nbsp;&nbsp; $1487531062 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 125622425 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $764485135 | &nbsp;&nbsp;&nbsp; 63888616 | &nbsp;&nbsp;&nbsp; $11.97 |
| Service Class | &nbsp;&nbsp;&nbsp; 723045927 | &nbsp;&nbsp;&nbsp; 61733809 | &nbsp;&nbsp;&nbsp;&nbsp;11.71 |

---

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Interest | &nbsp;&nbsp; $34002616 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 623833 |
| Other | &nbsp;&nbsp; 12453 |
| Total investment income | &nbsp;&nbsp; $34638902 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $3685246 |
| Distribution and/or service fees | &nbsp;&nbsp; 903040 |
| Shareholder servicing costs | &nbsp;&nbsp; 15263 |
| Administrative services fee | &nbsp;&nbsp; 102159 |
| Independent Trustees' compensation | &nbsp;&nbsp; 16543 |
| Custodian fee | &nbsp;&nbsp; 40917 |
| Shareholder communications | &nbsp;&nbsp; 21962 |
| Audit and tax fees | &nbsp;&nbsp; 45786 |
| Legal fees | &nbsp;&nbsp; 3935 |
| Miscellaneous | &nbsp;&nbsp; 45447 |
| Total expenses | &nbsp;&nbsp; $4880298 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (102484)<br>|
| Net expenses | &nbsp;&nbsp; $4777814 |
| Net investment income (loss) | &nbsp;&nbsp; $29861088 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $(3627267)<br>|
| Affiliated issuers | &nbsp;&nbsp; 1483 |
| Futures contracts | &nbsp;&nbsp; (5100193)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $(8725977)<br>|
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $30768754 |
| Affiliated issuers | &nbsp;&nbsp; (1369)<br>|
| Futures contracts | &nbsp;&nbsp; 6899836 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $37667221 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $28941244 |
| Change in net assets from operations | &nbsp;&nbsp; $58802332 |

---

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $29861088 | &nbsp;&nbsp; $62298929 |
| Net realized gain (loss) | (8725977)<br>| &nbsp;&nbsp; (14783045)<br>|
| Net unrealized gain (loss) | 37667221 | &nbsp;&nbsp; (10862810)<br>|
| Change in net assets from operations | $58802332 | &nbsp;&nbsp; $36653074 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(63326656)<br>|
| Change in net assets from fund share transactions | $(89289724)<br>| &nbsp;&nbsp; $8242307 |
| Total change in net assets | $(30487392)<br>| &nbsp;&nbsp; $(18431275)<br>|
| **Net assets** |  |  |
| At beginning of period | 1518018454 | &nbsp;&nbsp; 1536449729 |
| At end of period | $1487531062 | &nbsp;&nbsp; $1518018454 |

---

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $11.50 | &nbsp;&nbsp; $11.70 | &nbsp;&nbsp; $11.26 | &nbsp;&nbsp; $13.63 | &nbsp;&nbsp; $14.12 | &nbsp;&nbsp; $13.48 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.24 | &nbsp;&nbsp; $0.49 | &nbsp;&nbsp; $0.48 | &nbsp;&nbsp; $0.36 | &nbsp;&nbsp; $0.29 | &nbsp;&nbsp; $0.37 |
| Net realized and unrealized gain (loss) | 0.23 | &nbsp;&nbsp; (0.18)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.33 | &nbsp;&nbsp; (2.25)<br>| &nbsp;&nbsp; (0.40)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.76 |
| Total from investment operations | $0.47 | &nbsp;&nbsp; $0.31 | &nbsp;&nbsp; $0.81 | &nbsp;&nbsp; $(1.89)<br>| &nbsp;&nbsp; $(0.11)<br>| &nbsp;&nbsp; $1.13 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.51)<br>| &nbsp;&nbsp; $(0.37)<br>| &nbsp;&nbsp; $(0.34)<br>| &nbsp;&nbsp; $(0.38)<br>| &nbsp;&nbsp; $(0.49)<br>|
| From net realized gain |  |  |  | &nbsp;&nbsp; (0.14)<br>| &nbsp;&nbsp; (0.00)(w)<br>|  |
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(0.51)<br>| &nbsp;&nbsp; $(0.37)<br>| &nbsp;&nbsp; $(0.48)<br>| &nbsp;&nbsp; $(0.38)<br>| &nbsp;&nbsp; $(0.49)<br>|
| Net asset value, end of period (x) | $11.97 | &nbsp;&nbsp; $11.50 | &nbsp;&nbsp; $11.70 | &nbsp;&nbsp; $11.26 | &nbsp;&nbsp; $13.63 | &nbsp;&nbsp; $14.12 |
| Total return (%) (k)(r)(s)(x) | 4.09<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;2.55 | &nbsp;&nbsp;&nbsp;&nbsp;7.38 | &nbsp;&nbsp; (13.93)<br>| &nbsp;&nbsp; (0.81)<br>| &nbsp;&nbsp;&nbsp;&nbsp;8.47 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.54<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.54 | &nbsp;&nbsp;&nbsp;&nbsp;0.54 | &nbsp;&nbsp;&nbsp;&nbsp;0.54 | &nbsp;&nbsp;&nbsp;&nbsp;0.54 | &nbsp;&nbsp;&nbsp;&nbsp;0.54 |
| Expenses after expense reductions | 0.53<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.53 | &nbsp;&nbsp;&nbsp;&nbsp;0.52 | &nbsp;&nbsp;&nbsp;&nbsp;0.53 | &nbsp;&nbsp;&nbsp;&nbsp;0.53 | &nbsp;&nbsp;&nbsp;&nbsp;0.53 |
| Net investment income (loss) | 4.17<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;4.21 | &nbsp;&nbsp;&nbsp;&nbsp;4.17 | &nbsp;&nbsp;&nbsp;&nbsp;2.94 | &nbsp;&nbsp;&nbsp;&nbsp;2.10 | &nbsp;&nbsp;&nbsp;&nbsp;2.71 |
| Portfolio turnover rate | 29<br> (n)<br>| &nbsp;&nbsp; 66 | &nbsp;&nbsp; 58 | &nbsp;&nbsp; 120 | &nbsp;&nbsp; 161 | &nbsp;&nbsp; 112 |
| Net assets at end of period (000 omitted) | $764485 | &nbsp;&nbsp; $774145 | &nbsp;&nbsp; $752929 | &nbsp;&nbsp; $730323 | &nbsp;&nbsp; $928578 | &nbsp;&nbsp; $921342 |
| **Supplemental Rate:** |  |  |  |  |  |  |
| Portfolio turnover rate (excluding TBA transactions) (e) | 12<br> (n)<br>| &nbsp;&nbsp; 30 | &nbsp;&nbsp; 39 | &nbsp;&nbsp; N/A | &nbsp;&nbsp; N/A | &nbsp;&nbsp; N/A |

---

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $11.27 | &nbsp;&nbsp; $11.47 | &nbsp;&nbsp; $11.04 | &nbsp;&nbsp; $13.37 | &nbsp;&nbsp; $13.86 | &nbsp;&nbsp; $13.24 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.22 | &nbsp;&nbsp; $0.45 | &nbsp;&nbsp; $0.44 | &nbsp;&nbsp; $0.32 | &nbsp;&nbsp; $0.25 | &nbsp;&nbsp; $0.33 |
| Net realized and unrealized gain (loss) | 0.22 | &nbsp;&nbsp; (0.17)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.33 | &nbsp;&nbsp; (2.21)<br>| &nbsp;&nbsp; (0.40)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.74 |
| Total from investment operations | $0.44 | &nbsp;&nbsp; $0.28 | &nbsp;&nbsp; $0.77 | &nbsp;&nbsp; $(1.89)<br>| &nbsp;&nbsp; $(0.15)<br>| &nbsp;&nbsp; $1.07 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.48)<br>| &nbsp;&nbsp; $(0.34)<br>| &nbsp;&nbsp; $(0.30)<br>| &nbsp;&nbsp; $(0.34)<br>| &nbsp;&nbsp; $(0.45)<br>|
| From net realized gain |  |  |  | &nbsp;&nbsp; (0.14)<br>| &nbsp;&nbsp; (0.00)(w)<br>|  |
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(0.48)<br>| &nbsp;&nbsp; $(0.34)<br>| &nbsp;&nbsp; $(0.44)<br>| &nbsp;&nbsp; $(0.34)<br>| &nbsp;&nbsp; $(0.45)<br>|
| Net asset value, end of period (x) | $11.71 | &nbsp;&nbsp; $11.27 | &nbsp;&nbsp; $11.47 | &nbsp;&nbsp; $11.04 | &nbsp;&nbsp; $13.37 | &nbsp;&nbsp; $13.86 |
| Total return (%) (k)(r)(s)(x) | 3.90<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;2.33 | &nbsp;&nbsp;&nbsp;&nbsp;7.13 | &nbsp;&nbsp; (14.18)<br>| &nbsp;&nbsp; (1.07)<br>| &nbsp;&nbsp;&nbsp;&nbsp;8.17 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.79<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 | &nbsp;&nbsp;&nbsp;&nbsp;0.79 |
| Expenses after expense reductions | 0.78<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.77 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 | &nbsp;&nbsp;&nbsp;&nbsp;0.78 |
| Net investment income (loss) | 3.92<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;3.96 | &nbsp;&nbsp;&nbsp;&nbsp;3.92 | &nbsp;&nbsp;&nbsp;&nbsp;2.68 | &nbsp;&nbsp;&nbsp;&nbsp;1.85 | &nbsp;&nbsp;&nbsp;&nbsp;2.46 |
| Portfolio turnover rate | 29<br> (n)<br>| &nbsp;&nbsp; 66 | &nbsp;&nbsp; 58 | &nbsp;&nbsp; 120 | &nbsp;&nbsp; 161 | &nbsp;&nbsp; 112 |
| Net assets at end of period (000 omitted) | $723046 | &nbsp;&nbsp; $743873 | &nbsp;&nbsp; $783521 | &nbsp;&nbsp; $801789 | &nbsp;&nbsp; $1043338 | &nbsp;&nbsp; $1090009 |
| **Supplemental Rate:** |  |  |  |  |  |  |
| Portfolio turnover rate (excluding TBA transactions) (e) | 12<br> (n)<br>| &nbsp;&nbsp; 30 | &nbsp;&nbsp; 39 | &nbsp;&nbsp; N/A | &nbsp;&nbsp; N/A | &nbsp;&nbsp; N/A |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(e) Portfolio turnover rate (excluding TBA transactions) is disclosed beginning with the
 period ending December 31, 2023. Refer to Note 2 for more information on TBA transactions and mortgage dollar rolls.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(w) Per share amount was less than $0.01.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Total Return Bond Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Total Return Bond Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued. The fund invests in foreign securities. Investments in foreign securities are vulnerable to the effects of changes in the relative values of the local currency and the U.S. dollar and to the effects of changes in each country's market, economic, industrial, political, regulatory, geopolitical, environmental, public health, and other conditions.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, debt instruments and floating rate loans, including restricted debt instruments, are generally valued at an evaluated or composite bid as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Futures contracts are generally valued at last posted settlement price on their primary exchange as provided by a third-party pricing service. Futures contracts for which there were no trades that day for a particular position are generally valued at the closing bid quotation on their primary exchange as provided by a third-party pricing service. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. Pricing services generally value debt instruments assuming orderly transactions of institutional round lot sizes, but a fund may hold or transact in such securities in smaller, odd lot sizes. In instances where a fund holds an odd lot size position in a debt instrument, such position will typically be valued using the pricing agent's institutional round lot price for the debt instrument. Odd lots may trade at lower prices than institutional round lots, and the fund may receive different prices when it sells odd lot positions than it would receive for sales of institutional round lot positions. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments, such as futures contracts. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| U.S. Treasury Bonds & U.S. Government <br> Agencies & Equivalents<br>| $— | $342634986 | $— | $342634986 |
| Non - U.S. Sovereign Debt |  | 1818326 |  | 1818326 |
| Municipal Bonds |  | 26230492 |  | 26230492 |
| U.S. Corporate Bonds |  | 398773015 |  | 398773015 |
| Residential Mortgage-Backed Securities |  | 294799354 |  | 294799354 |
| Commercial Mortgage-Backed Securities |  | 74178144 |  | 74178144 |
| Asset-Backed Securities (including CDOs) |  | 185461101 |  | 185461101 |
| Foreign Bonds |  | 136971015 |  | 136971015 |
| Investment Companies | 27922099 |  |  | 27922099 |
| Total | $27922099 | $1460866433 | $— | $1488788532 |

---

---

| | | | |
|:---|:---|:---|:---|
| **Other Financial Instruments** |  |  |  |
| Futures Contracts – Assets | $3776175 | $— | $3776175 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Derivatives** — The fund uses derivatives primarily to increase or decrease exposure to a particular market or segment of the market, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives are used for hedging or non-hedging purposes. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. When the fund uses derivatives as an investment to increase market exposure, or for hedging purposes, gains and losses from derivative instruments may be substantially greater than the derivative's original cost.

The derivative instruments used by the fund during the period were futures contracts. Depending on the type of derivative, a fund may exit a derivative position by entering into an offsetting transaction with a counterparty or exchange, negotiating an agreement with the derivative counterparty, or novating the position to a third party. The fund may be unable to promptly close out a futures position in instances where the daily fluctuation in the price for that type of future exceeds the daily limit set by the exchange. The fund's period end derivatives, as presented in the Portfolio of Investments and the associated Derivative Contract tables, generally are indicative of the volume of its derivative activity during the period.

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

The following table presents, by major type of derivative contract, the fair value, on a gross basis, of the asset and liability components of derivatives held by the fund at June 30, 2025 as reported in the Statement of Assets and Liabilities:

---

| | | |
|:---|:---|:---|
|  |  | **Fair Value (a)** |
| **Risk** | **Derivative Contracts** | **Asset Derivatives** |
| Interest Rate | Futures Contracts | $3776175 |

---

(a) Values presented in this table for futures contracts correspond to the values reported in the Portfolio of Investments. Only the current day net variation margin for futures contracts is reported separately within the Statement of Assets and Liabilities.

The following table presents, by major type of derivative contract, the realized gain (loss) on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Futures** <br>**Contracts**<br>|
| Interest Rate | $(5100193)<br>|

---

The following table presents, by major type of derivative contract, the change in unrealized appreciation or depreciation on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Futures** <br>**Contracts**<br>|
| Interest Rate | $6899836 |

---

Derivative counterparty credit risk is managed through formal evaluation of the creditworthiness of all potential counterparties. On certain, but not all, uncleared derivatives, the fund attempts to reduce its exposure to counterparty credit risk whenever possible by entering into an ISDA Master Agreement on a bilateral basis. The ISDA Master Agreement gives each party to the agreement the right to terminate all transactions traded under such agreement if there is a specified deterioration in the credit quality of the other party. Upon an event of default or a termination of the ISDA Master Agreement, the non-defaulting party has the right to close out all transactions traded under such agreement and to net amounts owed under each agreement to one net amount payable by one party to the other. This right to close out and net payments across all transactions traded under the ISDA Master Agreement could result in a reduction of the fund's credit risk to such counterparty equal to any amounts payable by the fund under the applicable transactions, if any.

Collateral and margin requirements differ by type of derivative. For exchange-traded and cleared derivatives (e.g., futures contracts, cleared swaps, and exchange-traded options), margin requirements are set by the exchange or clearing broker and the clearing house and collateral, in the form of cash or securities, is posted by the fund directly with the exchange or clearing broker. Collateral terms are counterparty agreement specific for uncleared derivatives (e.g., forward foreign currency exchange contracts, uncleared swap agreements, and uncleared options). Collateral, in the form of cash and securities, is held in segregated accounts with the fund's custodian in connection with these agreements. For derivatives traded under an ISDA Master Agreement, which contains a credit support annex, the collateral requirements are netted across all transactions traded under such counterparty-specific agreement and an amount is posted from one party to the other to collateralize such obligations. Cash that has been segregated or delivered to cover the fund's collateral or margin obligations under derivative contracts, if any, will be reported separately in the Statement of Assets and Liabilities as restricted cash for uncleared derivatives and/or deposits with brokers for exchange-traded or cleared derivatives. Securities pledged as collateral or margin for the same purpose, if any, are noted in the Portfolio of Investments. The fund may be required to make payments of interest on uncovered collateral or margin obligations with the broker. Any such payments are included in "Miscellaneous" expense in the Statement of Operations.

**Futures Contracts** — The fund entered into futures contracts which may be used to hedge against or obtain broad market exposure, interest rate exposure, currency exposure, or to manage duration. A futures contract represents a commitment for the future purchase or sale of an asset at a specified price on a specified date.

Upon entering into a futures contract, the fund is required to deposit with the broker, either in cash or securities, an initial margin in an amount equal to a specified percentage of the notional amount of the contract. Subsequent payments (variation margin) are made or received by the fund each day, depending on the daily fluctuations in the value of the contract, and are recorded for financial statement purposes as unrealized gain or loss by the fund until the contract is closed or expires at which point the gain or loss on futures contracts is realized.

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

The fund bears the risk of interest rates, exchange rates or securities prices moving unexpectedly, in which case, the fund may not achieve the anticipated benefits of the futures contracts and may realize a loss. While futures contracts may present less counterparty risk to the fund since the contracts are exchange traded and the exchange's clearinghouse guarantees payments to the broker, there is still counterparty credit risk due to the insolvency of the broker. The fund's maximum risk of loss due to counterparty credit risk is equal to the margin posted by the fund to the broker plus any gains or minus any losses on the outstanding futures contracts.

**Mortgage-Backed/Asset-Backed Securities** — The fund invests a significant portion of its assets in asset-backed and/or mortgage-backed securities. For these securities, the value of the debt instrument also depends on the credit quality and adequacy of the underlying assets or collateral as well as whether there is a security interest in the underlying assets or collateral. Enforcing rights, if any, against the underlying assets or collateral may be difficult. U.S. Government securities not supported as to the payment of principal or interest by the U.S. Treasury, such as those issued by Fannie Mae, Freddie Mac, and the Federal Home Loan Banks, are subject to greater credit risk than are U.S. Government securities supported by the U.S. Treasury, such as those issued by Ginnie Mae.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Interest income is recorded on the accrual basis. All premium and discount is amortized or accreted for financial statement purposes in accordance with U.S. generally accepted accounting principles. Interest payments received in additional securities are recorded on the ex-interest date in an amount equal to the value of the security on such date. Debt obligations may be placed on non-accrual status or set to accrue at a rate of interest less than the contractual coupon when the collection of all or a portion of interest has become doubtful. Interest income for those debt obligations may be further reduced by the write-off of the related interest receivables when deemed uncollectible.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

The fund may purchase or sell mortgage-backed securities on a To Be Announced ("TBA") basis. A TBA transaction is subject to extended settlement and typically does not designate the actual security to be delivered, but instead includes an approximate principal amount. The price of the TBA security and the date that it will be settled are fixed at the time the transaction is negotiated. The value of the security varies with market fluctuations and no interest accrues to the fund until settlement takes place. TBA purchase and sale commitments are held at carrying amount, which approximates fair value and are categorized as level 2 within the fair value hierarchy and included in TBA purchase and TBA sale commitments in the Statement of Assets and Liabilities, as applicable. Losses may arise as a result of changes in the value of the TBA investment prior to settlement date or due to counterparty non-performance.

The fund may also enter into mortgage dollar rolls, typically TBA dollar rolls, in which the fund sells TBA mortgage-backed securities to financial institutions and simultaneously agrees to repurchase similar (same issuer, type and coupon) securities at a later date at an agreed-upon price. During the period between the sale and repurchase, the fund will not be entitled to receive interest and principal payments on the securities sold. The fund accounts for dollar roll transactions as purchases and sales and realizes gains and losses on these transactions. As such, these transactions may result in an increase to the fund's portfolio turnover rate. Portfolio turnover rates including and excluding TBA transactions are presented in the Financial Highlights. Dollar roll transactions involve the risk that the market value of the securities that the fund is required to purchase may decline below the agreed upon repurchase price of those securities.

The fund may purchase or sell securities on a when-issued or delayed delivery basis. In these extended settlement transactions, the receipt or delivery of the securities by the fund and related payments occur at a future date, usually beyond the customary settlement period. The price of such security and the date that the security will be settled are generally fixed at the time the transaction is negotiated. The value of the security varies with market fluctuations and for debt securities no interest accrues to the fund until settlement takes place. When the fund sells securities on a when-issued or delayed delivery basis, the fund typically owns or has the right to acquire securities equivalent in kind and amount to the securities sold. Purchase and sale commitments for when-issued or delayed delivery securities are held at carrying amount, which approximates fair value and are categorized as level 2 within the fair

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

value hierarchy, and included in When-issued investments purchased and When-issued investments sold in the Statement of Assets and Liabilities, as applicable. Losses may arise due to changes in the value of the underlying securities prior to settlement date or if the counterparty does not perform under the contract's terms, or if the issuer does not issue the securities.

To mitigate the counterparty credit risk on To Be Announced ("TBA") transactions, mortgage dollar rolls, and other types of forward settling mortgage-backed and asset-backed security transactions, the fund whenever possible enters into a Master Securities Forward Transaction Agreement ("MSFTA") on a bilateral basis with each of the counterparties with whom it undertakes a significant volume of transactions. The MSFTA gives each party to the agreement the right to terminate all transactions traded under such agreement if there is a specified deterioration in the credit quality of the other party. Upon an event of default or a termination of the MSFTA, the non-defaulting party has the right to close out all transactions traded under such agreement and to net amounts owed under each transaction to one net amount payable by one party to the other. This right to close out and net payments across all transactions traded under the MSFTA could result in a reduction of the fund's credit risk to such counterparty equal to any amounts payable by the fund under the applicable transactions, if any.

For mortgage-backed and asset-backed securities traded under a MSFTA, the collateral and margining requirements are contract specific. Collateral amounts across all transactions traded under such agreement are netted and an amount is posted from one party to the other to collateralize such obligations. Cash that has been pledged to cover the fund's collateral or margin obligations under a MSFTA, if any, will be reported separately on the Statement of Assets and Liabilities as restricted cash. Securities pledged as collateral or margin for the same purpose, if any, are noted in the Portfolio of Investments.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

Book/tax differences primarily relate to amortization of premium and accretion of discount of debt securities and derivative transactions.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $63326656 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $1549709368 |
| Gross appreciation | &nbsp;&nbsp; 12735720 |
| Gross depreciation | &nbsp;&nbsp; (73656556)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $(60920836)<br>|
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 64313587 |
| Capital loss carryforwards | &nbsp;&nbsp; (164418462)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; (92191081)<br>|

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

As of December 31, 2024, the fund had capital loss carryforwards available to offset future realized gains. These net capital losses may be carried forward indefinitely and their character is retained as short-term and/or long-term losses. Such losses are characterized as follows:

---

| | |
|:---|:---|
| Short-Term | $(50334133)<br>|
| Long-Term | (114084329)<br>|
| Total | $(164418462)<br>|

---

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $32633143 |
| Service Class |  | &nbsp;&nbsp; 30693513 |
| Total | $— | &nbsp;&nbsp; $63326656 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $2.5 billion | 0.50% |
| In excess of $2.5 billion and up to $5 billion | 0.45% |
| In excess of $5 billion | 0.40% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $102,484, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.49% of the fund's average daily net assets.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $14,445, which equated to 0.0020% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $818.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0139% of the fund's average daily net assets.

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 4 shares of Service Class for an aggregate amount of $42.

**(4) Portfolio Securities**

For the six months ended June 30, 2025, purchases and sales of investments, other than short-term obligations, were as follows:

---

| | | |
|:---|:---|:---|
|  | **Purchases** | **Sales** |
| U.S. Government securities | $359943281 | &nbsp;&nbsp; $381022936 |
| Non-U.S. Government securities | 69534619 | &nbsp;&nbsp; 100791270 |

---

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 3601211 | &nbsp;&nbsp; $42248927 | &nbsp;&nbsp; 9941803 | &nbsp;&nbsp; $115784755 |
| Service Class | 2422978 | &nbsp;&nbsp; 27821375 | &nbsp;&nbsp; 7771837 | &nbsp;&nbsp; 88796753 |
|  | 6024189 | &nbsp;&nbsp; $70070302 | &nbsp;&nbsp; 17713640 | &nbsp;&nbsp; $204581508 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 2742102 | &nbsp;&nbsp; $32027751 |
| Service Class |  |  | &nbsp;&nbsp; 2678317 | &nbsp;&nbsp; 30693513 |
|  |  | $— | &nbsp;&nbsp; 5420419 | &nbsp;&nbsp; $62721264 |
| Shares reacquired |  |  |  |  |
| Initial Class | (7051853)<br>| &nbsp;&nbsp; $(82395639)<br>| &nbsp;&nbsp; (9712558)<br>| &nbsp;&nbsp; $(113477404)<br>|
| Service Class | (6713561)<br>| &nbsp;&nbsp; (76964387)<br>| &nbsp;&nbsp; (12722949)<br>| &nbsp;&nbsp; (145583061)<br>|
|  | (13765414)<br>| &nbsp;&nbsp; $(159360026)<br>| &nbsp;&nbsp; (22435507)<br>| &nbsp;&nbsp; $(259060465)<br>|
| Net change |  |  |  |  |
| Initial Class | (3450642)<br>| &nbsp;&nbsp; $(40146712)<br>| &nbsp;&nbsp; 2971347 | &nbsp;&nbsp; $34335102 |
| Service Class | (4290583)<br>| &nbsp;&nbsp; (49143012)<br>| &nbsp;&nbsp; (2272795)<br>| &nbsp;&nbsp; (26092795)<br>|
|  | (7741225)<br>| &nbsp;&nbsp; $(89289724)<br>| &nbsp;&nbsp; 698552 | &nbsp;&nbsp; $8242307 |

---

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying funds for the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio and the MFS Conservative Allocation Portfolio were the owners of record of approximately 6% and 2%, respectively, of the value of outstanding voting shares of the fund. In addition, the MFS Growth Allocation Portfolio was the owner of record of less than 1% of the value of the outstanding voting shares of the fund.

------

MFS Total Return Bond Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $3,676 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $37508847 | &nbsp;&nbsp; $192270546 | &nbsp;&nbsp; $201857408 | &nbsp;&nbsp; $1483 | &nbsp;&nbsp; $(1369)<br>| &nbsp;&nbsp; $27922099 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $623833 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Total Return Bond Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Total Return Bond Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Total Return Bond Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

MFS Total Return Series

**ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

MFS Total Return Series

**Portfolio of Investments - 6/30/25 (unaudited)**

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – 59.9% | Common Stocks – 59.9% | Common Stocks – 59.9% |
| Aerospace & Defense – 2.5% | Aerospace & Defense – 2.5% |  |
| Boeing Co. (a) | 35661 | &nbsp;&nbsp; $7472050 |
| General Dynamics Corp. | 39765 | &nbsp;&nbsp; 11597860 |
| Honeywell International, Inc. | 57640 | &nbsp;&nbsp; 13423203 |
| L3Harris Technologies, Inc. | 59968 | &nbsp;&nbsp; 15042373 |
| Leidos Holdings, Inc. | 23674 | &nbsp;&nbsp; 3734810 |
|  |  | &nbsp;&nbsp; $51270296 |
| Alcoholic Beverages – 0.6% | Alcoholic Beverages – 0.6% |  |
| Constellation Brands, Inc., "A" | 48592 | &nbsp;&nbsp; $7904947 |
| Diageo PLC | 232762 | &nbsp;&nbsp; 5840472 |
|  |  | &nbsp;&nbsp; $13745419 |
| Apparel Manufacturers – 0.2% | Apparel Manufacturers – 0.2% |  |
| NIKE, Inc., "B" | 54106 | &nbsp;&nbsp; $3843690 |
| Automotive – 2.1% | Automotive – 2.1% |  |
| Aptiv PLC (a) | 260242 | &nbsp;&nbsp; $17753709 |
| Lear Corp. | 152287 | &nbsp;&nbsp; 14464219 |
| LKQ Corp. | 314777 | &nbsp;&nbsp; 11649897 |
|  |  | &nbsp;&nbsp; $43867825 |
| Broadcasting – 1.4% | Broadcasting – 1.4% |  |
| Interpublic Group of Companies, Inc. | 47386 | &nbsp;&nbsp; $1160009 |
| Omnicom Group, Inc. | 324441 | &nbsp;&nbsp; 23340286 |
| Warner Bros. Discovery, Inc. (a) | 485490 | &nbsp;&nbsp; 5563715 |
|  |  | &nbsp;&nbsp; $30064010 |
| Brokerage & Asset Managers – 3.4% | Brokerage & Asset Managers – 3.4% |  |
| Charles Schwab Corp. | 609988 | &nbsp;&nbsp; $55655305 |
| CME Group, Inc. | 54612 | &nbsp;&nbsp; 15052160 |
|  |  | &nbsp;&nbsp; $70707465 |
| Business Services – 2.5% | Business Services – 2.5% |  |
| Accenture PLC, "A" | 32490 | &nbsp;&nbsp; $9710936 |
| Amdocs Ltd. | 81459 | &nbsp;&nbsp; 7432319 |
| Cognizant Technology Solutions Corp., "A" | 122115 | &nbsp;&nbsp; 9528634 |
| Fidelity National Information Services, Inc. | 129165 | &nbsp;&nbsp; 10515323 |
| Fiserv, Inc. (a) | 82803 | &nbsp;&nbsp; 14276065 |
|  |  | &nbsp;&nbsp; $51463277 |
| Chemicals – 0.7% | Chemicals – 0.7% |  |
| PPG Industries, Inc. | 136526 | &nbsp;&nbsp; $15529833 |
| Computer Software – 1.7% | Computer Software – 1.7% |  |
| Microsoft Corp. | 73412 | &nbsp;&nbsp; $36515863 |

---

VTRFS-SEM

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Construction – 1.5% | Construction – 1.5% |  |
| Masco Corp. | 294483 | &nbsp;&nbsp; $18952926 |
| Mohawk Industries, Inc. (a) | 49049 | &nbsp;&nbsp; 5142297 |
| Stanley Black & Decker, Inc. | 101288 | &nbsp;&nbsp; 6862262 |
|  |  | &nbsp;&nbsp; $30957485 |
| Consumer Products – 1.4% | Consumer Products – 1.4% |  |
| Kenvue, Inc. | 1393276 | &nbsp;&nbsp; $29161267 |
| Containers – 0.3% | Containers – 0.3% |  |
| Avery Dennison Corp. | 17024 | &nbsp;&nbsp; $2987201 |
| Smurfit Westrock PLC | 99477 | &nbsp;&nbsp; 4292433 |
|  |  | &nbsp;&nbsp; $7279634 |
| Electrical Equipment – 1.5% | Electrical Equipment – 1.5% |  |
| Johnson Controls International PLC | 291181 | &nbsp;&nbsp; $30754537 |
| Electronics – 1.4% | Electronics – 1.4% |  |
| Intel Corp. | 510713 | &nbsp;&nbsp; $11439971 |
| NXP Semiconductors N.V. | 78325 | &nbsp;&nbsp; 17113229 |
|  |  | &nbsp;&nbsp; $28553200 |
| Energy - Independent – 2.4% | Energy - Independent – 2.4% |  |
| ConocoPhillips | 255602 | &nbsp;&nbsp; $22937723 |
| Hess Corp. | 192033 | &nbsp;&nbsp; 26604252 |
|  |  | &nbsp;&nbsp; $49541975 |
| Energy - Integrated – 1.5% | Energy - Integrated – 1.5% |  |
| Exxon Mobil Corp. | 170657 | &nbsp;&nbsp; $18396825 |
| Suncor Energy, Inc. | 342362 | &nbsp;&nbsp; 12824590 |
|  |  | &nbsp;&nbsp; $31221415 |
| Food & Beverages – 0.2% | Food & Beverages – 0.2% |  |
| Archer Daniels Midland Co. | 73592 | &nbsp;&nbsp; $3884186 |
| Health Maintenance Organizations – 1.7% | Health Maintenance Organizations – 1.7% |  |
| Cigna Group | 110127 | &nbsp;&nbsp; $36405784 |
| Insurance – 4.2% | Insurance – 4.2% |  |
| Aon PLC | 81278 | &nbsp;&nbsp; $28996739 |
| Chubb Ltd. | 85654 | &nbsp;&nbsp; 24815677 |
| Principal Financial Group, Inc. | 46525 | &nbsp;&nbsp; 3695481 |
| Travelers Cos., Inc. | 23930 | &nbsp;&nbsp; 6402232 |
| Willis Towers Watson PLC | 74398 | &nbsp;&nbsp; 22802987 |
|  |  | &nbsp;&nbsp; $86713116 |
| Interactive Media Services – 0.2% | Interactive Media Services – 0.2% |  |
| Alphabet, Inc., "A" | 18990 | &nbsp;&nbsp; $3346608 |
| Leisure & Toys – 0.5% | Leisure & Toys – 0.5% |  |
| Electronic Arts, Inc. | 65264 | &nbsp;&nbsp; $10422661 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Machinery & Tools – 1.4% | Machinery & Tools – 1.4% |  |
| AGCO Corp. | 69762 | &nbsp;&nbsp; $7196648 |
| Eaton Corp. PLC | 33167 | &nbsp;&nbsp; 11840287 |
| Regal Rexnord Corp. | 71441 | &nbsp;&nbsp; 10356088 |
|  |  | &nbsp;&nbsp; $29393023 |
| Major Banks – 7.0% | Major Banks – 7.0% |  |
| Bank of America Corp. | 738448 | &nbsp;&nbsp; $34943360 |
| Goldman Sachs Group, Inc. | 59143 | &nbsp;&nbsp; 41858458 |
| JPMorgan Chase & Co. | 104279 | &nbsp;&nbsp; 30231525 |
| Morgan Stanley | 100652 | &nbsp;&nbsp; 14177841 |
| PNC Financial Services Group, Inc. | 83196 | &nbsp;&nbsp; 15509398 |
| Wells Fargo & Co. | 122217 | &nbsp;&nbsp; 9792026 |
|  |  | &nbsp;&nbsp; $146512608 |
| Medical & Health Technology & Services – 1.1% | Medical & Health Technology & Services – 1.1% |  |
| ICON PLC (a) | 71593 | &nbsp;&nbsp; $10413202 |
| McKesson Corp. | 16721 | &nbsp;&nbsp; 12252814 |
|  |  | &nbsp;&nbsp; $22666016 |
| Medical Equipment – 3.8% | Medical Equipment – 3.8% |  |
| Agilent Technologies, Inc. | 78040 | &nbsp;&nbsp; $9209500 |
| Becton, Dickinson and Co. | 182728 | &nbsp;&nbsp; 31474898 |
| Medtronic PLC | 433774 | &nbsp;&nbsp; 37812080 |
|  |  | &nbsp;&nbsp; $78496478 |
| Metals & Mining – 0.2% | Metals & Mining – 0.2% |  |
| Glencore PLC | 1065078 | &nbsp;&nbsp; $4146172 |
| Other Banks & Diversified Financials – 1.5% | Other Banks & Diversified Financials – 1.5% |  |
| Northern Trust Corp. | 246680 | &nbsp;&nbsp; $31276557 |
| Pharmaceuticals – 3.8% | Pharmaceuticals – 3.8% |  |
| Johnson & Johnson | 219134 | &nbsp;&nbsp; $33472718 |
| Organon & Co. | 133281 | &nbsp;&nbsp; 1290160 |
| Pfizer, Inc. | 1354425 | &nbsp;&nbsp; 32831262 |
| Roche Holding AG | 35234 | &nbsp;&nbsp; 11474530 |
|  |  | &nbsp;&nbsp; $79068670 |
| Railroad & Shipping – 1.0% | Railroad & Shipping – 1.0% |  |
| Union Pacific Corp. | 88803 | &nbsp;&nbsp; $20431794 |
| Restaurants – 0.3% | Restaurants – 0.3% |  |
| U.S. Foods Holding Corp. (a) | 47773 | &nbsp;&nbsp; $3678999 |
| Wendy's Co. | 198266 | &nbsp;&nbsp; 2264197 |
|  |  | &nbsp;&nbsp; $5943196 |
| Specialty Chemicals – 1.1% | Specialty Chemicals – 1.1% |  |
| Air Products & Chemicals, Inc. | 16391 | &nbsp;&nbsp; $4623245 |
| Axalta Coating Systems Ltd. (a) | 298901 | &nbsp;&nbsp; 8874371 |
| DuPont de Nemours, Inc. | 144754 | &nbsp;&nbsp; 9928677 |
|  |  | &nbsp;&nbsp; $23426293 |
| Specialty Stores – 0.4% | Specialty Stores – 0.4% |  |
| Target Corp. | 83623 | &nbsp;&nbsp; $8249409 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Common Stocks – continued | Common Stocks – continued | Common Stocks – continued |
| Telecom Services – 1.6% | Telecom Services – 1.6% |  |
| Comcast Corp., "A" | 846184 | &nbsp;&nbsp; $30200307 |
| T-Mobile USA, Inc. | 10167 | &nbsp;&nbsp; 2422389 |
|  |  | &nbsp;&nbsp; $32622696 |
| Tobacco – 1.7% | Tobacco – 1.7% |  |
| Altria Group, Inc. | 86485 | &nbsp;&nbsp; $5070616 |
| Philip Morris International, Inc. | 167042 | &nbsp;&nbsp; 30423359 |
|  |  | &nbsp;&nbsp; $35493975 |
| Utilities - Electric Power – 3.1% | Utilities - Electric Power – 3.1% |  |
| Duke Energy Corp. | 138744 | &nbsp;&nbsp; $16371792 |
| Exelon Corp. | 193794 | &nbsp;&nbsp; 8414535 |
| National Grid PLC | 1010327 | &nbsp;&nbsp; 14721148 |
| PG&E Corp. | 1332129 | &nbsp;&nbsp; 18569878 |
| Southern Co. | 64995 | &nbsp;&nbsp; 5968491 |
|  |  | &nbsp;&nbsp; $64045844 |
| **Total Common Stocks (Identified Cost, $786,912,052)** |  | &nbsp;&nbsp; **$1247022277** |
| Bonds – 37.8% | Bonds – 37.8% | Bonds – 37.8% |
| Aerospace & Defense – 0.1% | Aerospace & Defense – 0.1% | Aerospace & Defense – 0.1% |
| BAE Systems PLC, 3.4%, 4/15/2030 (n) | $1108000 | &nbsp;&nbsp; $1057308 |
| Boeing Co., 5.805%, 5/01/2050  | 826000 | &nbsp;&nbsp; 792135 |
| Boeing Co., 6.858%, 5/01/2054  | 725000 | &nbsp;&nbsp; 793669 |
|  |  | &nbsp;&nbsp; $2643112 |
| Asset-Backed & Securitized – 6.2% | Asset-Backed & Securitized – 6.2% | Asset-Backed & Securitized – 6.2% |
| Affirm, Inc., 5.08%, 4/15/2030 (n) | $508773 | &nbsp;&nbsp; $509249 |
| AmeriCredit Automobile Receivables Trust, 2024-1, "A2-A", 5.75%, 2/18/2028  | 391809 | &nbsp;&nbsp; 392687 |
| Angel Oak Mortgage Trust, 2024-10, "A1", 5.348%, 10/25/2069 (n) | 2611624 | &nbsp;&nbsp; 2605850 |
| Angel Oak Mortgage Trust, 2024-12, "A1", 5.653%, 10/25/2069 (n) | 2334445 | &nbsp;&nbsp; 2339999 |
| Angel Oak Mortgage Trust, 2024-9, "A1", 5.138%, 9/25/2069 (n) | 1479203 | &nbsp;&nbsp; 1471342 |
| Arbor Realty Trust, Inc., CLO, 2021-FL3, "B", FLR, 6.026% ((SOFR - 1mo. + 0.11448%) + 1.6%), 8/15/2034 (n) | 1807500 | &nbsp;&nbsp; 1800322 |
| Arbor Realty Trust, Inc., CLO, 2022-FL1, "B", FLR, 6.404% (SOFR - 30 day + 2.1%), 1/15/2037 (n) | 5076500 | &nbsp;&nbsp; 5082843 |
| ARDN Mortgage Trust, 2025-ARCP, "A", FLR, 6.05% (SOFR - 1mo. + 1.75%), 6/15/2035 (n) | 3949000 | &nbsp;&nbsp; 3948980 |
| AREIT 2022-CRE6 Trust, "B", FLR, 6.151% (SOFR - 30 day + 1.85%), 1/20/2037 (n) | 3088500 | &nbsp;&nbsp; 3065025 |
| ARI Fleet Lease Trust, 2023-B, "A2", 6.05%, 7/15/2032 (n) | 254500 | &nbsp;&nbsp; 256535 |
| Bain Capital Credit CLO Ltd., 2020-3A, "BRR", FLR, 5.879% (SOFR - 3mo. + 1.6%), 10/23/2034 (n) | 2000000 | &nbsp;&nbsp; 2000704 |
| Bain Capital Credit CLO Ltd., 2020-4A, "A1R", FLR, 6.019% (SOFR - 3mo. + 1.75%), 10/20/2036 (n) | 3189862 | &nbsp;&nbsp; 3194966 |
| Bayview Financial Revolving Mortgage Loan Trust, FLR, 6.041% ((SOFR - 1mo. + 0.11448%) + 1.6%), 12/28/2040 (n) | 269585 | &nbsp;&nbsp; 551052 |
| Benchmark 2023-V3 Mortgage Trust, "A3", 6.363%, 7/15/2056  | 134138 | &nbsp;&nbsp; 140591 |
| Brazos Securitization LLC, 5.243%, 9/01/2040 (n) | 1552000 | &nbsp;&nbsp; 1545390 |
| BSPRT 2021-FL6 Issuer Ltd., "AS", FLR, 5.726% ((SOFR - 1mo. + 0.11448%) + 1.3%), 3/15/2036 (n) | 4889969 | &nbsp;&nbsp; 4878277 |
| BSPRT 2021-FL7 Issuer Ltd., "B", FLR, 6.476% ((SOFR - 1mo. + 0.11448%) + 2.05%), 12/15/2038 (n) | 849500 | &nbsp;&nbsp; 844475 |
| BSPRT 2022-FL8 Issuer Ltd., "B", FLR, 6.354% (SOFR - 30 day + 2.05%), 2/15/2037 (n) | 1817000 | &nbsp;&nbsp; 1809759 |
| Business Jet Securities LLC, 2024-1A, "A", 6.197%, 5/15/2039 (n) | 902138 | &nbsp;&nbsp; 921532 |
| BXMT 2021-FL4 Ltd., "AS", FLR, 5.728% ((SOFR - 1mo. + 0.11448%) + 1.3%), 5/15/2038 (n) | 5214000 | &nbsp;&nbsp; 5081233 |
| Chesapeake Funding II LLC, 2023-1A, "A1", 5.65%, 5/15/2035 (n) | 960127 | &nbsp;&nbsp; 964886 |
| Colt Funding LLC, 2024-5, "A1", 5.123%, 8/25/2069 (n) | 1692183 | &nbsp;&nbsp; 1685655 |
| Commercial Mortgage Pass-Through Certificates, 2023-BNK46, "A4", 5.745%, 8/15/2056  | 1872416 | &nbsp;&nbsp; 1960654 |
| Consumers 2023 Securitization Funding LLC, 5.55%, 3/01/2028  | 807590 | &nbsp;&nbsp; 813245 |
| Credit Acceptance Auto Loan Trust, 2023-3A, "A", 6.39%, 8/15/2033 (n) | 546000 | &nbsp;&nbsp; 550800 |
| Dryden Senior Loan Fund, 2013-26A, "AR", CLO, FLR, 5.417% ((SOFR - 3mo. + 0.26161%) + 0.9%), 4/15/2029 (n) | 630701 | &nbsp;&nbsp; 630813 |
| Dryden Senior Loan Fund, 2018-55A, "A1", CLO, FLR, 5.538% ((SOFR - 3mo. + 0.26161%) + 1.02%), 4/15/2031 (n) | 1750035 | &nbsp;&nbsp; 1750616 |
| Dwight 2025-FL1 Issuer LLC, "A", FLR, 5.962% (SOFR - 1mo. + 1.662%), 9/18/2042 (n) | 2946500 | &nbsp;&nbsp; 2940975 |
| ELM Trust, 2024-ELM, "B10", 5.995%, 6/10/2039 (n) | 2369972 | &nbsp;&nbsp; 2388439 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued | Asset-Backed & Securitized – continued |
| Empire District Bondco LLC, 4.943%, 1/01/2033  | $1113172 | &nbsp;&nbsp; $1120892 |
| Enterprise Fleet Financing 2023-3 LLC, "A2", 6.4%, 3/20/2030 (n) | 830838 | &nbsp;&nbsp; 843314 |
| Enterprise Fleet Financing 2024-4 LLC, "A2", 4.69%, 7/20/2027 (n) | 644000 | &nbsp;&nbsp; 644861 |
| GLS Auto Select Receivables Trust, 2023-1A, "A2", 6.27%, 8/16/2027 (n) | 141411 | &nbsp;&nbsp; 141600 |
| GLS Auto Select Receivables Trust, 2023-2A, 6.37%, 6/15/2028 (n) | 129870 | &nbsp;&nbsp; 130861 |
| GMAC Mortgage Corp. Loan Trust, FGIC, 5.805%, 10/25/2036  | 61032 | &nbsp;&nbsp; 60546 |
| Greystone Commercial Real Estate Notes, 2025-FL4, "AS", FLR, 6.45% (SOFR - 1mo. + 2.1385%), 1/15/2043 (n) | 548500 | &nbsp;&nbsp; 547249 |
| Hyundai Auto Lease Securitization Trust, 2025-B, 4.58%, 9/15/2027 (n) | 1334000 | &nbsp;&nbsp; 1338557 |
| Kubota Credit Owner Trust, 2023-2A, "A2", 5.61%, 7/15/2026 (n) | 192433 | &nbsp;&nbsp; 192635 |
| LoanCore 2021-CRE5 Ltd., "AS", FLR, 6.176% ((SOFR - 1mo. + 0.11448%) + 1.75%), 7/15/2036 (n) | 5288000 | &nbsp;&nbsp; 5286132 |
| Magnetite CLO Ltd., 2017-19A, FLR, 5.729% (SOFR - 3mo. + 1.45%), 4/17/2034 (n) | 889810 | &nbsp;&nbsp; 889413 |
| MF1 2020-FL4 Ltd., "A", FLR, 6.128% ((SOFR - 1mo. + 0.11448%) + 1.7%), 12/15/2035 (n) | 249939 | &nbsp;&nbsp; 250147 |
| MF1 2021-FL5 Ltd., "AS", FLR, 5.628% ((SOFR - 1mo. + 0.11448%) + 1.2%), 7/15/2036 (n) | 5187802 | &nbsp;&nbsp; 5175372 |
| MF1 2022-FL8 Ltd., "B", FLR, 6.267% (SOFR - 30 day + 1.95%), 2/19/2037 (n) | 2251053 | &nbsp;&nbsp; 2210183 |
| MF1 2024-FL15 LLC, "AS", FLR, 6.355% (SOFR - 1mo. + 2.04%), 8/18/2041 (n) | 2376000 | &nbsp;&nbsp; 2384167 |
| MF1 2024-FL16 LLC, "A", FLR, 5.855% (SOFR - 1mo. + 1.541%), 11/18/2039 (n) | 4793900 | &nbsp;&nbsp; 4802897 |
| MF1 2025-FL19 LLC, "A", FLR, 5.886% (SOFR - 1mo. + 1.572%), 2/18/2040 (n) | 2700000 | &nbsp;&nbsp; 2680328 |
| MF1 2025-FL19 LLC, "A", FLR, 5.802% (SOFR - 1mo. + 1.4881%), 5/18/2042 (n) | 2057523 | &nbsp;&nbsp; 2060092 |
| Morgan Stanley Bank of America Merrill Lynch Trust, 2017-C34, "A4", 3.536%, 11/15/2052  | 1600004 | &nbsp;&nbsp; 1562738 |
| MSWF Commercial Mortgage Trust, 2023-2, "A5", 6.014%, 12/15/2056  | 2080986 | &nbsp;&nbsp; 2228609 |
| Neuberger Berman CLO Ltd., 2013-15A, "BR2", FLR, 5.868% ((SOFR - 3mo. + 0.26161%) + 1.35%), 10/15/2029 (n) | 1750540 | &nbsp;&nbsp; 1751163 |
| Neuberger Berman CLO Ltd., 2015-20A, "A1R3", FLR, 5.468% (SOFR - 3mo. + 1.15%), 4/15/2039 (n) | 1900000 | &nbsp;&nbsp; 1902630 |
| Nissan Master Owner Trust, 2024-A, "A", FLR, 4.973% (SOFR - 1mo. + 0.67%), 2/15/2028 (n) | 1434737 | &nbsp;&nbsp; 1435821 |
| OBX Trust, 2024-NQM15, "A1", 5.316%, 10/25/2064 (n) | 997445 | &nbsp;&nbsp; 995583 |
| OBX Trust, 2025-NQM1, "A1", 5.547%, 12/25/2064 (n) | 1251812 | &nbsp;&nbsp; 1256217 |
| OneMain Financial Issuance Trust, 2022-3A, "A", 5.94%, 5/15/2034 (n) | 1286314 | &nbsp;&nbsp; 1293246 |
| Palmer Square Loan Funding 2024-3A Ltd., "A-2", FLR, 5.957% (SOFR - 3mo. + 1.65%), 8/08/2032 (n) | 4413018 | &nbsp;&nbsp; 4415344 |
| Parallel Ltd., 2023-1A, "A2R", FLR, 6.096% (SOFR - 3mo. + 1.8%), 7/20/2036 (n) | 1856072 | &nbsp;&nbsp; 1856072 |
| PFP III Ltd., 2025-12, "AS", 6.063%, 12/18/2042 (n) | 2892000 | &nbsp;&nbsp; 2886002 |
| PRM Trust, 2025-PRM6, "A", 4.48%, 7/05/2033 (n) | 1517909 | &nbsp;&nbsp; 1504851 |
| Provident Funding Mortgage Trust, 2025-2, "A4", 5.5%, 6/25/2055 (n) | 3706623 | &nbsp;&nbsp; 3710707 |
| ReadyCap Commercial Mortgage Trust, 2021-FL7, "B", FLR, 6.234% ((SOFR - 1mo. + 0.11448%) + 1.8%), 11/25/2036 (n) | 1130000 | &nbsp;&nbsp; 1123946 |
| Residential Funding Mortgage Securities, Inc., FGIC, 3.985%, 12/25/2035 (d)(q) | 63221 | &nbsp;&nbsp; 994 |
| Santander Drive Auto Receivables Trust, 2025-1, "A2", 4.76%, 8/16/2027  | 2366961 | &nbsp;&nbsp; 2367736 |
| SBNA Auto Lease Trust, 2024-C, "A2", 4.94%, 11/20/2026 (n) | 116115 | &nbsp;&nbsp; 116213 |
| Starwood Commercial Mortgage, 2022-FL3, "AS", FLR, 6.103% (SOFR - 30 day + 1.8%), 11/15/2038 (n) | 5210500 | &nbsp;&nbsp; 5173222 |
| Stellantis Finance US, Inc., 4.63%, 7/20/2027 (n) | 1649739 | &nbsp;&nbsp; 1653705 |
| TPG Real Estate Finance, 2021-FL4, "A", FLR, 5.628% ((SOFR - 1mo. + 0.11448%) + 1.2%), 3/15/2038 (n) | 2183655 | &nbsp;&nbsp; 2175919 |
| Verus Securitization Trust, 2024-8, "A1", 5.364%, 10/25/2069 (n) | 588698 | &nbsp;&nbsp; 588344 |
| Virginia Power Fuel Securitization LLC, 5.088%, 5/01/2027  | 891303 | &nbsp;&nbsp; 896124 |
| Voya CLO 2012-4A Ltd., "A2R3", FLR, 5.968% ((SOFR - 3mo. + 0.26161%) + 1.45%), 10/15/2030 (n) | 2010166 | &nbsp;&nbsp; 2011115 |
|  |  | &nbsp;&nbsp; $129792441 |
| Automotive – 0.1% | Automotive – 0.1% | Automotive – 0.1% |
| Stellantis Finance US, Inc., 2.691%, 9/15/2031 (n) | $2741000 | &nbsp;&nbsp; $2316453 |
| Brokerage & Asset Managers – 0.5% | Brokerage & Asset Managers – 0.5% | Brokerage & Asset Managers – 0.5% |
| Charles Schwab Corp., 5.853% to 5/19/2033, FLR (SOFR - 1 day + 2.5%) to 5/19/2034  | $3534000 | &nbsp;&nbsp; $3754208 |
| Intercontinental Exchange, Inc., 2.1%, 6/15/2030  | 2038000 | &nbsp;&nbsp; 1825681 |
| LPL Holdings, Inc., 6.75%, 11/17/2028  | 336000 | &nbsp;&nbsp; 358345 |
| LPL Holdings, Inc., 4.375%, 5/15/2031 (n) | 3770000 | &nbsp;&nbsp; 3607073 |
|  |  | &nbsp;&nbsp; $9545307 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Building – 0.2% | Building – 0.2% | Building – 0.2% |
| Martin Marietta Materials, Inc., 2.5%, 3/15/2030  | $179000 | &nbsp;&nbsp; $164249 |
| Masco Corp., 2%, 2/15/2031  | 3622000 | &nbsp;&nbsp; 3115210 |
| Vulcan Materials Co., 3.5%, 6/01/2030  | 359000 | &nbsp;&nbsp; 343453 |
|  |  | &nbsp;&nbsp; $3622912 |
| Business Services – 0.4% | Business Services – 0.4% | Business Services – 0.4% |
| Equinix, Inc., 1.8%, 7/15/2027  | $1405000 | &nbsp;&nbsp; $1339304 |
| Equinix, Inc., 2.5%, 5/15/2031  | 1931000 | &nbsp;&nbsp; 1710830 |
| Experian Finance PLC, 4.25%, 2/01/2029 (n) | 1450000 | &nbsp;&nbsp; 1446393 |
| Fiserv, Inc., 2.65%, 6/01/2030  | 690000 | &nbsp;&nbsp; 632382 |
| Global Payments, Inc., 2.9%, 11/15/2031  | 778000 | &nbsp;&nbsp; 688121 |
| Verisk Analytics, Inc., 4.125%, 3/15/2029  | 1756000 | &nbsp;&nbsp; 1744194 |
| Verisk Analytics, Inc., 5.75%, 4/01/2033  | 1346000 | &nbsp;&nbsp; 1415430 |
|  |  | &nbsp;&nbsp; $8976654 |
| Cable TV – 0.3% | Cable TV – 0.3% | Cable TV – 0.3% |
| Charter Communications Operating LLC/Charter Communications Operating Capital Corp., 6.384%, 10/23/2035  | $996000 | &nbsp;&nbsp; $1046107 |
| Charter Communications Operating LLC/Charter Communications Operating Capital Corp., 3.5%, 6/01/2041  | 2007000 | &nbsp;&nbsp; 1456066 |
| Charter Communications Operating LLC/Charter Communications Operating Capital Corp., 5.375%, 5/01/2047  | 406000 | &nbsp;&nbsp; 352372 |
| Charter Communications Operating LLC/Charter Communications Operating Capital Corp., 5.25%, 4/01/2053  | 1639000 | &nbsp;&nbsp; 1392481 |
| Time Warner Entertainment Co. LP, 8.375%, 7/15/2033  | 2390000 | &nbsp;&nbsp; 2783118 |
|  |  | &nbsp;&nbsp; $7030144 |
| Chemicals – 0.1% | Chemicals – 0.1% | Chemicals – 0.1% |
| RPM International, Inc., 2.95%, 1/15/2032  | $1349000 | &nbsp;&nbsp; $1189521 |
| Computer Software – 0.1% | Computer Software – 0.1% | Computer Software – 0.1% |
| Oracle Corp., 4.9%, 2/06/2033  | $700000 | &nbsp;&nbsp; $701873 |
| Roper Technologies, Inc., 2%, 6/30/2030  | 1231000 | &nbsp;&nbsp; 1093898 |
|  |  | &nbsp;&nbsp; $1795771 |
| Conglomerates – 0.1% | Conglomerates – 0.1% | Conglomerates – 0.1% |
| Westinghouse Air Brake Technologies Corp., 4.7%, 9/15/2028  | $1998000 | &nbsp;&nbsp; $2009458 |
| Consumer Products – 0.0% | Consumer Products – 0.0% | Consumer Products – 0.0% |
| Kenvue, Inc., 4.9%, 3/22/2033  | $778000 | &nbsp;&nbsp; $789509 |
| Consumer Services – 0.1% | Consumer Services – 0.1% | Consumer Services – 0.1% |
| Booking Holdings, Inc., 4.625%, 4/13/2030  | $1353000 | &nbsp;&nbsp; $1368547 |
| Electrical Equipment – 0.1% | Electrical Equipment – 0.1% | Electrical Equipment – 0.1% |
| Arrow Electronics, Inc., 2.95%, 2/15/2032  | $2544000 | &nbsp;&nbsp; $2233262 |
| Electronics – 0.1% | Electronics – 0.1% | Electronics – 0.1% |
| Broadcom, Inc., 4.3%, 11/15/2032  | $1257000 | &nbsp;&nbsp; $1219284 |
| Broadcom, Inc., 4.926%, 5/15/2037 (n) | 646000 | &nbsp;&nbsp; 626958 |
|  |  | &nbsp;&nbsp; $1846242 |
| Energy - Independent – 0.2% | Energy - Independent – 0.2% | Energy - Independent – 0.2% |
| Diamondback Energy, Inc., 5.4%, 4/18/2034  | $1254000 | &nbsp;&nbsp; $1257711 |
| EQT Corp., 5.75%, 2/01/2034  | 2788000 | &nbsp;&nbsp; 2882701 |
|  |  | &nbsp;&nbsp; $4140412 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Energy - Integrated – 0.5% | Energy - Integrated – 0.5% | Energy - Integrated – 0.5% |
| BP Capital Markets America, Inc., 2.721%, 1/12/2032  | $3955000 | &nbsp;&nbsp; $3536006 |
| Eni S.p.A., 4.75%, 9/12/2028 (n) | 3564000 | &nbsp;&nbsp; 3602579 |
| Eni S.p.A., 5.5%, 5/15/2034 (n) | 3488000 | &nbsp;&nbsp; 3513636 |
|  |  | &nbsp;&nbsp; $10652221 |
| Financial Institutions – 0.5% | Financial Institutions – 0.5% | Financial Institutions – 0.5% |
| AerCap Ireland Capital DAC/AerCap Global Aviation Trust, 2.45%, 10/29/2026  | $3996000 | &nbsp;&nbsp; $3893209 |
| AerCap Ireland Capital DAC/AerCap Global Aviation Trust, 3.65%, 7/21/2027  | 2176000 | &nbsp;&nbsp; 2142984 |
| Avolon Holdings Funding Ltd., 4.375%, 5/01/2026 (n) | 682000 | &nbsp;&nbsp; 677889 |
| Avolon Holdings Funding Ltd., 3.25%, 2/15/2027 (n) | 2065000 | &nbsp;&nbsp; 2012893 |
| Avolon Holdings Funding Ltd., 2.528%, 11/18/2027 (n) | 1722000 | &nbsp;&nbsp; 1636907 |
|  |  | &nbsp;&nbsp; $10363882 |
| Food & Beverages – 0.4% | Food & Beverages – 0.4% | Food & Beverages – 0.4% |
| Anheuser-Busch InBev Worldwide, Inc., 4.375%, 4/15/2038  | $697000 | &nbsp;&nbsp; $650349 |
| Anheuser-Busch InBev Worldwide, Inc., 8%, 11/15/2039  | 2791000 | &nbsp;&nbsp; 3531979 |
| Diageo Capital PLC, 2.375%, 10/24/2029  | 2415000 | &nbsp;&nbsp; 2241424 |
| Keurig Dr Pepper, Inc., 3.2%, 5/01/2030  | 287000 | &nbsp;&nbsp; 270595 |
| Mars, Inc., 5.2%, 3/01/2035 (n) | 2014000 | &nbsp;&nbsp; 2038126 |
|  |  | &nbsp;&nbsp; $8732473 |
| Gaming & Lodging – 0.3% | Gaming & Lodging – 0.3% | Gaming & Lodging – 0.3% |
| GLP Capital LP/GLP Financing II, Inc., 5.3%, 1/15/2029  | $1507000 | &nbsp;&nbsp; $1523710 |
| Las Vegas Sands Corp., 3.9%, 8/08/2029  | 783000 | &nbsp;&nbsp; 745506 |
| Marriott International, Inc., 4.625%, 6/15/2030  | 1871000 | &nbsp;&nbsp; 1875429 |
| Marriott International, Inc., 2.85%, 4/15/2031  | 7000 | &nbsp;&nbsp; 6356 |
| Marriott International, Inc., 2.75%, 10/15/2033  | 1512000 | &nbsp;&nbsp; 1287115 |
|  |  | &nbsp;&nbsp; $5438116 |
| Insurance – 0.6% | Insurance – 0.6% | Insurance – 0.6% |
| AIA Group Ltd., 3.375%, 4/07/2030 (n) | $2338000 | &nbsp;&nbsp; $2241703 |
| Corebridge Financial, Inc., 3.9%, 4/05/2032  | 2911000 | &nbsp;&nbsp; 2732296 |
| Corebridge Financial, Inc., 5.75%, 1/15/2034  | 1170000 | &nbsp;&nbsp; 1215536 |
| Metropolitan Life Global Funding I, 3.3%, 3/21/2029 (n) | 3972000 | &nbsp;&nbsp; 3829725 |
| Sammons Financial Group, Inc., 6.875%, 4/15/2034 (n) | 3038000 | &nbsp;&nbsp; 3252731 |
|  |  | &nbsp;&nbsp; $13271991 |
| Insurance - Health – 0.2% | Insurance - Health – 0.2% | Insurance - Health – 0.2% |
| Humana, Inc., 5.875%, 3/01/2033  | $1161000 | &nbsp;&nbsp; $1199819 |
| UnitedHealth Group, Inc., 5%, 4/15/2034  | 1975000 | &nbsp;&nbsp; 1974242 |
|  |  | &nbsp;&nbsp; $3174061 |
| Insurance - Property & Casualty – 0.4% | Insurance - Property & Casualty – 0.4% | Insurance - Property & Casualty – 0.4% |
| Aon Corp., 4.5%, 12/15/2028  | $1872000 | &nbsp;&nbsp; $1881068 |
| Brown & Brown, Inc., 4.2%, 3/17/2032  | 2009000 | &nbsp;&nbsp; 1922199 |
| Brown & Brown, Inc., 5.55%, 6/23/2035  | 484000 | &nbsp;&nbsp; 493553 |
| Fairfax Financial Holdings Ltd., 5.625%, 8/16/2032  | 3838000 | &nbsp;&nbsp; 3941694 |
| Fairfax Financial Holdings Ltd., 6%, 12/07/2033  | 88000 | &nbsp;&nbsp; 91783 |
| Liberty Mutual Group, Inc., 3.951%, 10/15/2050 (n) | 1027000 | &nbsp;&nbsp; 750867 |
|  |  | &nbsp;&nbsp; $9081164 |
| International Market Quasi-Sovereign – 0.0% | International Market Quasi-Sovereign – 0.0% | International Market Quasi-Sovereign – 0.0% |
| Electricite de France S.A., 6.9%, 5/23/2053 (n) | $629000 | &nbsp;&nbsp; $671201 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Machinery & Tools – 0.2% | Machinery & Tools – 0.2% | Machinery & Tools – 0.2% |
| Ashtead Capital, Inc., 5.5%, 8/11/2032 (n) | $3748000 | &nbsp;&nbsp; $3795718 |
| Major Banks – 2.4% | Major Banks – 2.4% | Major Banks – 2.4% |
| Bank of America Corp., 3.5%, 4/19/2026  | $1361000 | &nbsp;&nbsp; $1351578 |
| Bank of America Corp., 2.572% to 10/20/2031, FLR (SOFR - 1 day + 1.21%) to 10/20/2032  | 3265000 | &nbsp;&nbsp; 2877644 |
| Barclays PLC, 2.894% to 11/24/2031, FLR (CMT - 1yr. + 1.3%) to 11/24/2032  | 877000 | &nbsp;&nbsp; 776176 |
| Barclays PLC, 7.437% to 11/02/2032, FLR (CMT - 1yr. + 3.5%) to 11/02/2033  | 2463000 | &nbsp;&nbsp; 2795382 |
| Capital One Financial Corp., 3.273% to 3/01/2029, FLR (SOFR - 1 day + 1.79%) to 3/01/2030  | 4286000 | &nbsp;&nbsp; 4099597 |
| Deutsche Bank AG, 7.146% to 7/13/2026, FLR (SOFR - 1 day + 2.52%) to 7/13/2027  | 838000 | &nbsp;&nbsp; 859173 |
| Deutsche Bank AG, 2.311% to 11/16/2026, FLR (SOFR - 1 day + 1.219%) to 11/16/2027  | 880000 | &nbsp;&nbsp; 853840 |
| Deutsche Bank AG, 6.72% to 1/18/2028, FLR (SOFR - 1 day + 3.18%) to 1/18/2029  | 2180000 | &nbsp;&nbsp; 2290030 |
| Goldman Sachs Group, Inc., 2.6%, 2/07/2030  | 2135000 | &nbsp;&nbsp; 1973113 |
| Goldman Sachs Group, Inc., 2.383% to 7/21/2031, FLR (SOFR - 1 day + 1.248%) to 7/21/2032  | 2678000 | &nbsp;&nbsp; 2338820 |
| HSBC Holdings PLC, 4.7% to 9/09/2031, FLR (CMT - 1yr. + 3.25%) to 9/09/2169  | 922000 | &nbsp;&nbsp; 835746 |
| HSBC Holdings PLC, 4% to 9/09/2026, FLR (CMT - 1yr. + 3.222%) to 9/09/2170  | 442000 | &nbsp;&nbsp; 434527 |
| JPMorgan Chase & Co., 2.956% to 5/13/2030, FLR (SOFR - 1 day + 2.515%) to 5/13/2031  | 449000 | &nbsp;&nbsp; 415190 |
| JPMorgan Chase & Co., 2.545% to 11/08/2031, FLR (SOFR - 1 day + 1.18%) to 11/08/2032  | 4380000 | &nbsp;&nbsp; 3855907 |
| JPMorgan Chase & Co., 2.963% to 1/25/2032, FLR (SOFR - 1 day + 1.26%) to 1/25/2033  | 1684000 | &nbsp;&nbsp; 1513631 |
| JPMorgan Chase & Co., 5.766%, 4/22/2035  | 3830000 | &nbsp;&nbsp; 4023755 |
| JPMorgan Chase & Co., 3.897% to 1/23/2048, FLR ((SOFR - 3mo. + 0.26161%) + 1.22%) to 1/23/2049  | 886000 | &nbsp;&nbsp; 699667 |
| Mitsubishi UFJ Financial Group, Inc., 2.852% to 1/19/2032, FLR (CMT - 1yr. + 1.1%) to 1/19/2033  | 2471000 | &nbsp;&nbsp; 2188972 |
| Morgan Stanley, 2.699% to 1/22/2030, FLR (SOFR - 1 day + 1.143%) to 1/22/2031  | 2348000 | &nbsp;&nbsp; 2165129 |
| Morgan Stanley, 2.943% to 1/21/2032, FLR (SOFR - 1 day + 1.29%) to 1/21/2033  | 2960000 | &nbsp;&nbsp; 2641783 |
| Sumitomo Mitsui Financial Group, Inc., 2.472%, 1/14/2029  | 4946000 | &nbsp;&nbsp; 4643740 |
| UBS Group AG, 2.095% to 2/11/2031, FLR (CMT - 1yr. + 1.0%) to 2/11/2032 (n) | 6069000 | &nbsp;&nbsp; 5249539 |
|  |  | &nbsp;&nbsp; $48882939 |
| Medical & Health Technology & Services – 0.4% | Medical & Health Technology & Services – 0.4% | Medical & Health Technology & Services – 0.4% |
| Adventist Health System/West, 5.43%, 3/01/2032  | $2533000 | &nbsp;&nbsp; $2543996 |
| Alcon Finance Corp., 2.6%, 5/27/2030 (n) | 302000 | &nbsp;&nbsp; 276087 |
| Cigna Corp., 3.2%, 3/15/2040  | 474000 | &nbsp;&nbsp; 362959 |
| CVS Health Corp., 5.3%, 6/01/2033  | 2392000 | &nbsp;&nbsp; 2412271 |
| HCA, Inc., 5.125%, 6/15/2039  | 1827000 | &nbsp;&nbsp; 1718256 |
| Northwell Healthcare, Inc., 3.979%, 11/01/2046  | 153000 | &nbsp;&nbsp; 117618 |
| Northwell Healthcare, Inc., 4.26%, 11/01/2047  | 1139000 | &nbsp;&nbsp; 905426 |
|  |  | &nbsp;&nbsp; $8336613 |
| Medical Equipment – 0.1% | Medical Equipment – 0.1% | Medical Equipment – 0.1% |
| Boston Scientific Corp., 2.65%, 6/01/2030  | $1503000 | &nbsp;&nbsp; $1391435 |
| Metals & Mining – 0.4% | Metals & Mining – 0.4% | Metals & Mining – 0.4% |
| Anglo American Capital PLC, 3.875%, 3/16/2029 (n) | $496000 | &nbsp;&nbsp; $484439 |
| Anglo American Capital PLC, 5.625%, 4/01/2030 (n) | 1394000 | &nbsp;&nbsp; 1446099 |
| Anglo American Capital PLC, 2.625%, 9/10/2030 (n) | 4316000 | &nbsp;&nbsp; 3902005 |
| Glencore Funding LLC, 2.5%, 9/01/2030 (n) | 1602000 | &nbsp;&nbsp; 1443461 |
| Glencore Funding LLC, 2.85%, 4/27/2031 (n) | 670000 | &nbsp;&nbsp; 604066 |
|  |  | &nbsp;&nbsp; $7880070 |
| Midstream – 0.4% | Midstream – 0.4% | Midstream – 0.4% |
| Enbridge, Inc., 5.625%, 4/05/2034  | $1870000 | &nbsp;&nbsp; $1921266 |
| Plains All American Pipeline LP, 3.8%, 9/15/2030  | 1779000 | &nbsp;&nbsp; 1700231 |
| Sabine Pass Liquefaction LLC, 4.5%, 5/15/2030  | 485000 | &nbsp;&nbsp; 484189 |
| Spectra Energy Partners LP, 3.375%, 10/15/2026  | 783000 | &nbsp;&nbsp; 772027 |
| Targa Resources Corp., 4.2%, 2/01/2033  | 704000 | &nbsp;&nbsp; 659648 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Midstream – continued | Midstream – continued | Midstream – continued |
| Targa Resources Corp., 6.125%, 3/15/2033  | $2157000 | &nbsp;&nbsp; $2273271 |
|  |  | &nbsp;&nbsp; $7810632 |
| Mortgage-Backed – 9.8% | Mortgage-Backed – 9.8% |  |
| Fannie Mae, 5%, 3/01/2026 - 3/01/2041  | $1233627 | &nbsp;&nbsp; $1246932 |
| Fannie Mae, 3%, 11/01/2028 - 9/01/2046  | 1348104 | &nbsp;&nbsp; 1281593 |
| Fannie Mae, 6.5%, 6/01/2031 - 7/01/2037  | 465207 | &nbsp;&nbsp; 485210 |
| Fannie Mae, 2.5%, 11/01/2031  | 38040 | &nbsp;&nbsp; 36559 |
| Fannie Mae, 5.5%, 2/01/2033 - 8/01/2038  | 2657425 | &nbsp;&nbsp; 2714001 |
| Fannie Mae, 3%, 2/25/2033 (i) | 177228 | &nbsp;&nbsp; 12362 |
| Fannie Mae, 4.5%, 8/01/2033 - 6/01/2044  | 2833937 | &nbsp;&nbsp; 2819269 |
| Fannie Mae, 6%, 1/01/2034 - 7/01/2037  | 1593648 | &nbsp;&nbsp; 1649138 |
| Fannie Mae, 3.5%, 4/01/2038 - 7/01/2046  | 7978640 | &nbsp;&nbsp; 7441763 |
| Fannie Mae, 3.25%, 5/25/2040  | 59309 | &nbsp;&nbsp; 56573 |
| Fannie Mae, 4%, 9/01/2040 - 6/01/2047  | 5520278 | &nbsp;&nbsp; 5319154 |
| Fannie Mae, 5.306%, 2/25/2045 (n) | 735195 | &nbsp;&nbsp; 735652 |
| Fannie Mae, 2%, 4/25/2046  | 127907 | &nbsp;&nbsp; 118832 |
| Fannie Mae, 4%, 7/25/2046 (i) | 234334 | &nbsp;&nbsp; 43417 |
| Fannie Mae, UMBS, 5.5%, 10/01/2025 - 11/01/2053  | 6798324 | &nbsp;&nbsp; 6812055 |
| Fannie Mae, UMBS, 2%, 9/01/2035 - 2/01/2052  | 11736695 | &nbsp;&nbsp; 9740836 |
| Fannie Mae, UMBS, 2.5%, 7/01/2037 - 6/01/2052  | 24909452 | &nbsp;&nbsp; 21075011 |
| Fannie Mae, UMBS, 5%, 10/01/2037 - 6/01/2053  | 3115956 | &nbsp;&nbsp; 3065961 |
| Fannie Mae, UMBS, 4.5%, 4/01/2038 - 9/01/2052  | 1491695 | &nbsp;&nbsp; 1434852 |
| Fannie Mae, UMBS, 1.5%, 2/01/2042 - 4/01/2052  | 2605949 | &nbsp;&nbsp; 1969316 |
| Fannie Mae, UMBS, 3%, 6/01/2051 - 8/01/2052  | 8817325 | &nbsp;&nbsp; 7676253 |
| Fannie Mae, UMBS, 3.5%, 5/01/2052 - 7/01/2052  | 4089584 | &nbsp;&nbsp; 3688601 |
| Fannie Mae, UMBS, 4%, 11/01/2052 - 5/01/2053  | 576151 | &nbsp;&nbsp; 536749 |
| Fannie Mae, UMBS, 6%, 12/01/2052 - 8/01/2054  | 4497947 | &nbsp;&nbsp; 4574109 |
| Freddie Mac, 0.775%, 6/25/2027 (i) | 13682000 | &nbsp;&nbsp; 182585 |
| Freddie Mac, 0.866%, 6/25/2027 (i) | 4330759 | &nbsp;&nbsp; 48763 |
| Freddie Mac, 0.696%, 7/25/2027 (i) | 11340346 | &nbsp;&nbsp; 108283 |
| Freddie Mac, 0.457%, 8/25/2027 (i) | 9650000 | &nbsp;&nbsp; 70064 |
| Freddie Mac, 0.539%, 8/25/2027 (i) | 6171916 | &nbsp;&nbsp; 47212 |
| Freddie Mac, 0.406%, 9/25/2027 (i) | 10419000 | &nbsp;&nbsp; 73003 |
| Freddie Mac, 0.324%, 11/25/2027 (i) | 16290000 | &nbsp;&nbsp; 76078 |
| Freddie Mac, 0.407%, 11/25/2027 (i) | 11035303 | &nbsp;&nbsp; 59649 |
| Freddie Mac, 0.449%, 11/25/2027 (i) | 9845591 | &nbsp;&nbsp; 66578 |
| Freddie Mac, 0.378%, 12/25/2027 (i) | 10109000 | &nbsp;&nbsp; 64565 |
| Freddie Mac, 0.417%, 12/25/2027 (i) | 11210000 | &nbsp;&nbsp; 84252 |
| Freddie Mac, 0.487%, 12/25/2027 (i) | 16759446 | &nbsp;&nbsp; 131756 |
| Freddie Mac, 1.214%, 7/25/2029 (i) | 808120 | &nbsp;&nbsp; 30027 |
| Freddie Mac, 1.261%, 8/25/2029 - 9/25/2030 (i) | 5876097 | &nbsp;&nbsp; 244346 |
| Freddie Mac, 1.913%, 4/25/2030 (i) | 900000 | &nbsp;&nbsp; 67258 |
| Freddie Mac, 1.954%, 4/25/2030 (i) | 2701417 | &nbsp;&nbsp; 206404 |
| Freddie Mac, 1.769%, 5/25/2030 (i) | 1301002 | &nbsp;&nbsp; 93332 |
| Freddie Mac, 1.907%, 5/25/2030 (i) | 3334078 | &nbsp;&nbsp; 256187 |
| Freddie Mac, 1.435%, 6/25/2030 (i) | 1327631 | &nbsp;&nbsp; 77545 |
| Freddie Mac, 1.701%, 8/25/2030 (i) | 1191673 | &nbsp;&nbsp; 85202 |
| Freddie Mac, 1.17%, 11/25/2030 (i) | 1356411 | &nbsp;&nbsp; 68699 |
| Freddie Mac, 0.413%, 1/25/2031 (i) | 5286931 | &nbsp;&nbsp; 73728 |
| Freddie Mac, 0.871%, 1/25/2031 (i) | 2233850 | &nbsp;&nbsp; 85191 |
| Freddie Mac, 1.026%, 1/25/2031 (i) | 1493151 | &nbsp;&nbsp; 67359 |
| Freddie Mac, 0.607%, 3/25/2031 (i) | 4262073 | &nbsp;&nbsp; 100671 |
| Freddie Mac, 0.828%, 3/25/2031 (i) | 1837683 | &nbsp;&nbsp; 68354 |
| Freddie Mac, 1.323%, 5/25/2031 (i) | 822353 | &nbsp;&nbsp; 50039 |
| Freddie Mac, 1.039%, 7/25/2031 (i) | 1237840 | &nbsp;&nbsp; 61601 |
| Freddie Mac, 0.606%, 8/25/2031 (i) | 1661407 | &nbsp;&nbsp; 42978 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Mortgage-Backed – continued | Mortgage-Backed – continued |  |
| Freddie Mac, 0.632%, 9/25/2031 (i) | $5442448 | &nbsp;&nbsp; $159524 |
| Freddie Mac, 0.955%, 9/25/2031 (i) | 1567181 | &nbsp;&nbsp; 70111 |
| Freddie Mac, 0.441%, 11/25/2031 (i) | 8030040 | &nbsp;&nbsp; 159779 |
| Freddie Mac, 0.596%, 12/25/2031 (i) | 7179988 | &nbsp;&nbsp; 196528 |
| Freddie Mac, 0.664%, 12/25/2031 (i) | 12162189 | &nbsp;&nbsp; 369249 |
| Freddie Mac, 0.426%, 11/25/2032 (i) | 8112877 | &nbsp;&nbsp; 124240 |
| Freddie Mac, 5%, 9/01/2033 - 1/15/2040  | 634077 | &nbsp;&nbsp; 643569 |
| Freddie Mac, 5.5%, 12/01/2033 - 2/01/2037  | 391473 | &nbsp;&nbsp; 398925 |
| Freddie Mac, 6%, 4/01/2034 - 6/01/2037  | 570005 | &nbsp;&nbsp; 592729 |
| Freddie Mac, 6.5%, 5/01/2034 - 7/01/2037  | 274474 | &nbsp;&nbsp; 286937 |
| Freddie Mac, 4.5%, 4/01/2035 - 5/01/2042  | 458763 | &nbsp;&nbsp; 458043 |
| Freddie Mac, 5.5%, 2/15/2036 (i) | 40101 | &nbsp;&nbsp; 6402 |
| Freddie Mac, 4%, 8/01/2037 - 4/01/2044  | 1755142 | &nbsp;&nbsp; 1694584 |
| Freddie Mac, 3.5%, 11/01/2037 - 10/25/2058  | 4873106 | &nbsp;&nbsp; 4575892 |
| Freddie Mac, 3%, 1/01/2038 - 2/25/2059  | 6499303 | &nbsp;&nbsp; 5862749 |
| Freddie Mac, 4.5%, 12/15/2040 (i) | 16122 | &nbsp;&nbsp; 1498 |
| Freddie Mac, 4%, 8/15/2044 (i) | 38547 | &nbsp;&nbsp; 3453 |
| Freddie Mac, UMBS, 2%, 12/01/2031 - 4/01/2052  | 12232014 | &nbsp;&nbsp; 9831998 |
| Freddie Mac, UMBS, 6.5%, 10/01/2034 - 11/01/2054  | 1487702 | &nbsp;&nbsp; 1543345 |
| Freddie Mac, UMBS, 5%, 10/01/2035 - 8/01/2053  | 1686052 | &nbsp;&nbsp; 1662076 |
| Freddie Mac, UMBS, 6%, 1/01/2036 - 6/01/2054  | 1540411 | &nbsp;&nbsp; 1568130 |
| Freddie Mac, UMBS, 3%, 4/01/2037 - 8/01/2052  | 8505345 | &nbsp;&nbsp; 7381667 |
| Freddie Mac, UMBS, 3.5%, 12/01/2046 - 5/01/2052  | 1040815 | &nbsp;&nbsp; 956361 |
| Freddie Mac, UMBS, 4%, 8/01/2047 - 5/01/2052  | 1200717 | &nbsp;&nbsp; 1130295 |
| Freddie Mac, UMBS, 2.5%, 4/01/2048 - 9/01/2052  | 11529333 | &nbsp;&nbsp; 9608882 |
| Freddie Mac, UMBS, 1.5%, 3/01/2051 - 10/01/2051  | 1481570 | &nbsp;&nbsp; 1116443 |
| Freddie Mac, UMBS, 5.5%, 7/01/2052 - 4/01/2053  | 590357 | &nbsp;&nbsp; 596618 |
| Freddie Mac, UMBS, 4.5%, 10/01/2052  | 2691075 | &nbsp;&nbsp; 2578966 |
| Ginnie Mae, 6%, 9/15/2032 - 1/15/2038  | 692931 | &nbsp;&nbsp; 719882 |
| Ginnie Mae, 5.5%, 5/15/2033 - 10/20/2053  | 4299800 | &nbsp;&nbsp; 4332692 |
| Ginnie Mae, 4.5%, 7/20/2033 - 12/20/2052  | 6730033 | &nbsp;&nbsp; 6512794 |
| Ginnie Mae, 5%, 7/20/2033 - 12/20/2054  | 5146917 | &nbsp;&nbsp; 5070998 |
| Ginnie Mae, 4%, 1/20/2041 - 10/20/2052  | 4376888 | &nbsp;&nbsp; 4119904 |
| Ginnie Mae, 4.532%, 9/20/2041  | 709324 | &nbsp;&nbsp; 691127 |
| Ginnie Mae, 3.5%, 12/15/2041 - 10/20/2052  | 5612366 | &nbsp;&nbsp; 5172797 |
| Ginnie Mae, 3%, 4/20/2045 - 10/20/2052  | 8984176 | &nbsp;&nbsp; 7994808 |
| Ginnie Mae, 2.5%, 8/20/2051 - 4/20/2052  | 11000442 | &nbsp;&nbsp; 9350538 |
| Ginnie Mae, 2%, 1/20/2052 - 3/20/2052  | 8758347 | &nbsp;&nbsp; 7134485 |
| Ginnie Mae, 6.5%, 7/20/2054 - 3/20/2055  | 916332 | &nbsp;&nbsp; 942034 |
| Ginnie Mae, TBA, 6%, 8/01/2055  | 2375000 | &nbsp;&nbsp; 2407002 |
| UMBS, TBA, 2%, 7/01/2040 - 8/01/2055  | 5600000 | &nbsp;&nbsp; 4780594 |
| UMBS, TBA, 3%, 7/01/2055  | 1175000 | &nbsp;&nbsp; 1016540 |
| UMBS, TBA, 6.5%, 7/01/2055  | 3500000 | &nbsp;&nbsp; 3613668 |
| UMBS, TBA, 2.5%, 8/01/2055  | 25000 | &nbsp;&nbsp; 20730 |
|  |  | &nbsp;&nbsp; $204685493 |
| Municipals – 0.5% | Municipals – 0.5% | Municipals – 0.5% |
| Massachusetts Educational Financing Authority, Education Loan Rev., Taxable, "A", 6.352%, 7/01/2049  | $2745000 | &nbsp;&nbsp; $2821427 |
| New Jersey Turnpike Authority Rev., Taxable (Build America Bonds), "F", 7.414%, 1/01/2040  | 3685000 | &nbsp;&nbsp; 4403740 |
| Rhode Island Student Loan Authority Education Loan Rev., Taxable, "1", 6.081%, 12/01/2042  | 2305000 | &nbsp;&nbsp; 2370354 |
| State of Florida, Taxable, "A", 2.154%, 7/01/2030  | 1032000 | &nbsp;&nbsp; 923383 |
|  |  | &nbsp;&nbsp; $10518904 |
| Natural Gas - Distribution – 0.0% | Natural Gas - Distribution – 0.0% | Natural Gas - Distribution – 0.0% |
| NiSource, Inc., 5.65%, 2/01/2045  | $414000 | &nbsp;&nbsp; $403742 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| Natural Gas - Pipeline – 0.0% | Natural Gas - Pipeline – 0.0% | Natural Gas - Pipeline – 0.0% |
| APA Infrastructure Ltd., 4.25%, 7/15/2027 (n) | $253000 | &nbsp;&nbsp; $251844 |
| Network & Telecom – 0.1% | Network & Telecom – 0.1% | Network & Telecom – 0.1% |
| Verizon Communications, Inc., 3.15%, 3/22/2030  | $995000 | &nbsp;&nbsp; $943066 |
| Verizon Communications, Inc., 4.812%, 3/15/2039  | 1775000 | &nbsp;&nbsp; 1665520 |
|  |  | &nbsp;&nbsp; $2608586 |
| Oils – 0.1% | Oils – 0.1% | Oils – 0.1% |
| Phillips 66 Co., 2.15%, 12/15/2030  | $2775000 | &nbsp;&nbsp; $2443754 |
| Pollution Control – 0.3% | Pollution Control – 0.3% | Pollution Control – 0.3% |
| Republic Services, Inc., 1.45%, 2/15/2031  | $804000 | &nbsp;&nbsp; $685731 |
| Waste Management, Inc., 4.875%, 2/15/2034  | 5465000 | &nbsp;&nbsp; 5540002 |
|  |  | &nbsp;&nbsp; $6225733 |
| Real Estate - Office – 0.1% | Real Estate - Office – 0.1% | Real Estate - Office – 0.1% |
| Boston Properties LP, REIT, 2.55%, 4/01/2032  | $1244000 | &nbsp;&nbsp; $1049458 |
| Real Estate - Other – 0.2% | Real Estate - Other – 0.2% | Real Estate - Other – 0.2% |
| Public Storage Operating, REIT, 5.1%, 8/01/2033  | $4057000 | &nbsp;&nbsp; $4162664 |
| Real Estate - Retail – 0.1% | Real Estate - Retail – 0.1% | Real Estate - Retail – 0.1% |
| Brixmor Operating Partnership LP, REIT, 4.125%, 5/15/2029  | $162000 | &nbsp;&nbsp; $159295 |
| Brixmor Operating Partnership LP, REIT, 4.05%, 7/01/2030  | 1589000 | &nbsp;&nbsp; 1541514 |
| Realty Income Corp., REIT, 3.25%, 1/15/2031  | 458000 | &nbsp;&nbsp; 429296 |
|  |  | &nbsp;&nbsp; $2130105 |
| Retailers – 0.1% | Retailers – 0.1% | Retailers – 0.1% |
| Alimentation Couche-Tard, Inc., 3.439%, 5/13/2041 (n) | $2106000 | &nbsp;&nbsp; $1566244 |
| Specialty Stores – 0.2% | Specialty Stores – 0.2% | Specialty Stores – 0.2% |
| Genuine Parts Co., 2.75%, 2/01/2032  | $3528000 | &nbsp;&nbsp; $3072615 |
| Telecommunications - Wireless – 0.5% | Telecommunications - Wireless – 0.5% | Telecommunications - Wireless – 0.5% |
| Crown Castle, Inc., REIT, 3.65%, 9/01/2027  | $2426000 | &nbsp;&nbsp; $2384229 |
| Rogers Communications, Inc., 3.8%, 3/15/2032  | 4915000 | &nbsp;&nbsp; 4567299 |
| T-Mobile USA, Inc., 2.05%, 2/15/2028  | 1789000 | &nbsp;&nbsp; 1690934 |
| Vodafone Group PLC, 5.625%, 2/10/2053  | 708000 | &nbsp;&nbsp; 667963 |
|  |  | &nbsp;&nbsp; $9310425 |
| Tobacco – 0.4% | Tobacco – 0.4% | Tobacco – 0.4% |
| B.A.T. International Finance PLC, 4.448%, 3/16/2028  | $4521000 | &nbsp;&nbsp; $4528244 |
| Philip Morris International, Inc., 5.125%, 11/17/2027  | 822000 | &nbsp;&nbsp; 838443 |
| Philip Morris International, Inc., 5.625%, 11/17/2029  | 354000 | &nbsp;&nbsp; 371713 |
| Philip Morris International, Inc., 5.125%, 2/15/2030  | 1329000 | &nbsp;&nbsp; 1367310 |
| Philip Morris International, Inc., 5.75%, 11/17/2032  | 1564000 | &nbsp;&nbsp; 1653457 |
|  |  | &nbsp;&nbsp; $8759167 |
| Transportation - Services – 0.0% | Transportation - Services – 0.0% | Transportation - Services – 0.0% |
| ERAC USA Finance LLC, 7%, 10/15/2037 (n) | $716000 | &nbsp;&nbsp; $821668 |
| U.S. Government Agencies and Equivalents – 0.0% | U.S. Government Agencies and Equivalents – 0.0% | U.S. Government Agencies and Equivalents – 0.0% |
| Small Business Administration, 5.11%, 8/01/2025  | $18397 | &nbsp;&nbsp; $18393 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Bonds – continued | Bonds – continued | Bonds – continued |
| U.S. Treasury Obligations – 9.0% | U.S. Treasury Obligations – 9.0% | U.S. Treasury Obligations – 9.0% |
| U.S. Treasury Bonds, 2.375%, 2/15/2042  | $2900000 | &nbsp;&nbsp; $2109750 |
| U.S. Treasury Bonds, 2.875%, 5/15/2043  | 9096000 | &nbsp;&nbsp; 7010671 |
| U.S. Treasury Bonds, 4.5%, 2/15/2044  | 2600000 | &nbsp;&nbsp; 2512250 |
| U.S. Treasury Bonds, 2.5%, 2/15/2045  | 9797000 | &nbsp;&nbsp; 6896935 |
| U.S. Treasury Bonds, 3%, 11/15/2045  | 3638000 | &nbsp;&nbsp; 2771559 |
| U.S. Treasury Bonds, 2.25%, 8/15/2046  | 46200000 | &nbsp;&nbsp; 30266414 |
| U.S. Treasury Bonds, 2.875%, 5/15/2049  | 900000 | &nbsp;&nbsp; 646066 |
| U.S. Treasury Bonds, 2.25%, 2/15/2052  | 7800000 | &nbsp;&nbsp; 4764398 |
| U.S. Treasury Bonds, 4%, 11/15/2052  | 2700000 | &nbsp;&nbsp; 2361340 |
| U.S. Treasury Bonds, 4.125%, 8/15/2053  | 5100000 | &nbsp;&nbsp; 4555535 |
| U.S. Treasury Bonds, 4.75%, 11/15/2053  | 8000000 | &nbsp;&nbsp; 7927500 |
| U.S. Treasury Bonds, 4.25%, 2/15/2054  | 12900000 | &nbsp;&nbsp; 11767219 |
| U.S. Treasury Notes, 2.5%, 3/31/2027  | 19407000 | &nbsp;&nbsp; 18992327 |
| U.S. Treasury Notes, 4.5%, 4/15/2027 (f) | 36800000 | &nbsp;&nbsp; 37258563 |
| U.S. Treasury Notes, 4.25%, 6/30/2029  | 18100000 | &nbsp;&nbsp; 18436547 |
| U.S. Treasury Notes, 3.875%, 4/30/2030  | 9500000 | &nbsp;&nbsp; 9537109 |
| U.S. Treasury Notes, 4.25%, 11/15/2034  | 19800000 | &nbsp;&nbsp; 19864969 |
|  |  | &nbsp;&nbsp; $187679152 |
| Utilities - Electric Power – 1.0% | Utilities - Electric Power – 1.0% | Utilities - Electric Power – 1.0% |
| American Electric Power Co., Inc., 5.95%, 11/01/2032  | $1205000 | &nbsp;&nbsp; $1277427 |
| American Transmission Systems, Inc., 2.65%, 1/15/2032 (n) | 235000 | &nbsp;&nbsp; 206755 |
| Duke Energy Carolinas LLC, 4.95%, 1/15/2033  | 3779000 | &nbsp;&nbsp; 3845109 |
| Duke Energy Corp., 4.5%, 8/15/2032  | 2858000 | &nbsp;&nbsp; 2794365 |
| Enel Finance International N.V., 7.05%, 10/14/2025 (n) | 926000 | &nbsp;&nbsp; 931444 |
| Enel Finance International N.V., 4.75%, 5/25/2047 (n) | 392000 | &nbsp;&nbsp; 329791 |
| Exelon Corp., 4.05%, 4/15/2030  | 1543000 | &nbsp;&nbsp; 1517917 |
| Georgia Power Co., 3.7%, 1/30/2050  | 138000 | &nbsp;&nbsp; 102854 |
| Jersey Central Power & Light Co., 4.3%, 1/15/2026 (n) | 1333000 | &nbsp;&nbsp; 1330366 |
| Jersey Central Power & Light Co., 2.75%, 3/01/2032 (n) | 873000 | &nbsp;&nbsp; 765310 |
| Jersey Central Power & Light Co., 5.1%, 1/15/2035  | 629000 | &nbsp;&nbsp; 627141 |
| Oncor Electric Delivery Co. LLC, 5.75%, 3/15/2029  | 2007000 | &nbsp;&nbsp; 2102877 |
| Pacific Gas & Electric Co., 2.1%, 8/01/2027  | 453000 | &nbsp;&nbsp; 429034 |
| Pacific Gas & Electric Co., 3%, 6/15/2028  | 1333000 | &nbsp;&nbsp; 1265950 |
| Pacific Gas & Electric Co., 2.5%, 2/01/2031  | 1643000 | &nbsp;&nbsp; 1426208 |
| Pacific Gas & Electric Co., 3.3%, 8/01/2040  | 926000 | &nbsp;&nbsp; 662457 |
| Xcel Energy, Inc., 3.4%, 6/01/2030  | 968000 | &nbsp;&nbsp; 918331 |
|  |  | &nbsp;&nbsp; $20533336 |
| Utilities - Gas – 0.0% | Utilities - Gas – 0.0% | Utilities - Gas – 0.0% |
| East Ohio Gas Co., 2%, 6/15/2030 (n) | $1073000 | &nbsp;&nbsp; $953967 |
| **Total Bonds (Identified Cost, $817,919,218)** |  | &nbsp;&nbsp; **$785977511** |
| Preferred Stocks – 0.9% | Preferred Stocks – 0.9% | Preferred Stocks – 0.9% |
| Computer Software - Systems – 0.4% |  |  |
| Samsung Electronics Co. Ltd. | 197759 | &nbsp;&nbsp; $7253312 |
| Consumer Products – 0.5% |  |  |
| Henkel AG & Co. KGaA | 135515 | &nbsp;&nbsp; $10640935 |
| **Total Preferred Stocks (Identified Cost, $18,935,949)** |  | &nbsp;&nbsp; **$17894247** |
| Convertible Preferred Stocks – 0.3% | Convertible Preferred Stocks – 0.3% | Convertible Preferred Stocks – 0.3% |
| Aerospace & Defense – 0.3% | Aerospace & Defense – 0.3% |  |
| Boeing Co., 6% (Identified Cost, $4,643,750) | 92875 | &nbsp;&nbsp; $6315500 |

---

------

MFS Total Return Series

*Portfolio of Investments (unaudited) – continued*

---

| | | |
|:---|:---|:---|
| **Issuer** | **Shares/Par** | **Value ($)** |
| Mutual Funds (h) – 1.3% | Mutual Funds (h) – 1.3% | Mutual Funds (h) – 1.3% |
| Money Market Funds – 1.3% | Money Market Funds – 1.3% |  |
| MFS Institutional Money Market Portfolio, 4.35% (v) (Identified Cost, $27,079,907) | 27080850 | &nbsp;&nbsp; $27083558 |
| Other Assets, Less Liabilities – (0.2)% |  | &nbsp;&nbsp; (3746096) |
| **Net Assets – 100.0%** | **Net Assets – 100.0%** | &nbsp;&nbsp; **$2080546997** |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Non-income producing security.

&nbsp;&nbsp;&nbsp;&nbsp;(d) In default.

&nbsp;&nbsp;&nbsp;&nbsp;(f) All or a portion of the security has been segregated as collateral for open futures
 contracts.

&nbsp;&nbsp;&nbsp;&nbsp;(h) An affiliated issuer, which may be considered one in which the fund owns 5% or more
 of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated
 issuers and in unaffiliated issuers were $27,083,558 and $2,057,209,535, respectively.

&nbsp;&nbsp;&nbsp;&nbsp;(i) Interest only security for which the fund receives interest on notional principal
 (Par amount). Par amount shown is the notional principal and does not reflect the cost of the security.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933.
 These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers.
 At period end, the aggregate value of these securities was $176,624,522, representing 8.5% of net assets.

&nbsp;&nbsp;&nbsp;&nbsp;(q) Interest received was less than stated coupon rate.

&nbsp;&nbsp;&nbsp;&nbsp;(v) Affiliated issuer that is available only to investment companies managed by MFS. The
 rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

---

| | |
|:---|:---|
| The following abbreviations are used in this report and are defined: | The following abbreviations are used in this report and are defined: |
| CLO | Collateralized Loan Obligation |
| CMT | Constant Maturity Treasury |
| FGIC | Financial Guaranty Insurance Co. |
| FLR | Floating Rate. Interest rate resets periodically based on the parenthetically disclosed reference rate plus a spread (if any). The period-end rate <br> reported may not be the current rate. All reference rates are USD unless otherwise noted.<br>|
| REIT | Real Estate Investment Trust |
| SOFR | Secured Overnight Financing Rate |
| TBA | To Be Announced |
| UMBS | Uniform Mortgage-Backed Security |

---

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** | **Derivative Contracts at 6/30/25** |
| **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** | **Futures Contracts** |
| **Description** | &nbsp;&nbsp; **Long/** <br>**Short**<br>| **Currency** | **Contracts** | &nbsp;&nbsp; **Notional** <br>**Amount**<br>| &nbsp;&nbsp;&nbsp; **Expiration** <br>**Date**<br>| &nbsp;&nbsp; **Value/Unrealized** <br>**Appreciation** <br>&nbsp;&nbsp;&nbsp;&nbsp;**(Depreciation)**<br>|
| **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** | **Asset Derivatives** |
| ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** | ***Interest Rate Futures*** |  |  |
| U.S. Treasury Note 2 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 265 | &nbsp;&nbsp;&nbsp; $55126211 | September – 2025 | &nbsp;&nbsp;&nbsp; $227748 |
| U.S. Treasury Note 5 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 210 | &nbsp;&nbsp;&nbsp; 22890000 | September – 2025 | &nbsp;&nbsp;&nbsp; 213991 |
| U.S. Treasury Ultra Bond 30 yr | &nbsp;&nbsp;&nbsp; Long | &nbsp;&nbsp;&nbsp; USD | &nbsp;&nbsp;&nbsp; 82 | &nbsp;&nbsp;&nbsp; 9768250 | September – 2025 | &nbsp;&nbsp;&nbsp; 406909 |
|  |  |  |  |  |  | &nbsp;&nbsp;&nbsp; $848648 |

---

At June 30, 2025, the fund had liquid securities with an aggregate value of $1,052,958 to cover any collateral or margin obligations for certain derivative contracts.

**See Notes to Financial Statements**

------

MFS Total Return Series

**Financial Statements** \| **Statement of Assets and Liabilities** 

**(unaudited)**

This statement represents your fund's balance sheet, which details the assets and liabilities comprising the total value of the fund.

---

| | |
|:---|:---|
| **At 6/30/25** <br> **Assets**<br>|  |
| Investments in unaffiliated issuers, at value (identified cost, $1,628,410,969) | &nbsp;&nbsp; $2057209535 |
| Investments in affiliated issuers, at value (identified cost, $27,079,907) | &nbsp;&nbsp; 27083558 |
| Foreign currency, at value (identified cost, $2) | &nbsp;&nbsp; 2 |
| Receivables for |  |
| Net daily variation margin on open futures contracts | &nbsp;&nbsp; 152617 |
| TBA sale commitments | &nbsp;&nbsp; 1100070 |
| Fund shares sold | &nbsp;&nbsp; 378986 |
| Interest and dividends | &nbsp;&nbsp; 8897441 |
| Receivable from investment adviser | &nbsp;&nbsp; 8335 |
| Other assets | &nbsp;&nbsp; 2299 |
| Total assets | &nbsp;&nbsp; $2094832843 |
| **Liabilities** |  |
| Payable to custodian | &nbsp;&nbsp; $5657 |
| Payables for |  |
| TBA purchase commitments | &nbsp;&nbsp; 12822035 |
| Fund shares reacquired | &nbsp;&nbsp; 1207941 |
| Payable to affiliates |  |
| Administrative services fee | &nbsp;&nbsp; 2989 |
| Shareholder servicing costs | &nbsp;&nbsp; 995 |
| Distribution and/or service fees | &nbsp;&nbsp; 30983 |
| Payable for independent Trustees' compensation | &nbsp;&nbsp; 7357 |
| Accrued expenses and other liabilities | &nbsp;&nbsp; 207889 |
| Total liabilities | &nbsp;&nbsp; $14285846 |
| Net assets | &nbsp;&nbsp; $2080546997 |
| **Net assets consist of** |  |
| Paid-in capital | &nbsp;&nbsp; $1371728512 |
| Total distributable earnings (loss) | &nbsp;&nbsp; 708818485 |
| Net assets | &nbsp;&nbsp; $2080546997 |
| Shares of beneficial interest outstanding | &nbsp;&nbsp; 86358154 |

---

---

| | | | |
|:---|:---|:---|:---|
|  | **Net assets** | &nbsp;&nbsp; **Shares** <br>**outstanding**<br>| &nbsp;&nbsp; **Net asset value** <br>**per share**<br>|
| Initial Class | &nbsp;&nbsp;&nbsp; $944291881 | &nbsp;&nbsp;&nbsp; 38582024 | &nbsp;&nbsp;&nbsp; $24.47 |
| Service Class | &nbsp;&nbsp;&nbsp; 1136255116 | &nbsp;&nbsp;&nbsp; 47776130 | &nbsp;&nbsp;&nbsp;&nbsp;23.78 |

---

**See Notes to Financial Statements**

------

MFS Total Return Series

**Financial Statements** \| **Statement of Operations (unaudited)**

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

---

| | |
|:---|:---|
| **Six months ended 6/30/25** |  |
| **Net investment income (loss)** |  |
| Income |  |
| Interest | &nbsp;&nbsp; $17555646 |
| Dividends from unaffiliated issuers | &nbsp;&nbsp; 15407492 |
| Dividends from affiliated issuers | &nbsp;&nbsp; 185723 |
| Other | &nbsp;&nbsp; 11142 |
| Income on securities loaned | &nbsp;&nbsp; 2460 |
| Foreign taxes withheld | &nbsp;&nbsp; (189619)<br>|
| Total investment income | &nbsp;&nbsp; $32972844 |
| Expenses |  |
| Management fee | &nbsp;&nbsp; $6928533 |
| Distribution and/or service fees | &nbsp;&nbsp; 1397964 |
| Shareholder servicing costs | &nbsp;&nbsp; 22362 |
| Administrative services fee | &nbsp;&nbsp; 140341 |
| Independent Trustees' compensation | &nbsp;&nbsp; 22924 |
| Custodian fee | &nbsp;&nbsp; 60570 |
| Shareholder communications | &nbsp;&nbsp; 29664 |
| Audit and tax fees | &nbsp;&nbsp; 40786 |
| Legal fees | &nbsp;&nbsp; 5616 |
| Miscellaneous | &nbsp;&nbsp; 40263 |
| Total expenses | &nbsp;&nbsp; $8689023 |
| Reduction of expenses by investment adviser | &nbsp;&nbsp; (1013125)<br>|
| Net expenses | &nbsp;&nbsp; $7675898 |
| Net investment income (loss) | &nbsp;&nbsp; $25296946 |
| **Realized and unrealized gain (loss)** |  |
| Realized gain (loss) (identified cost basis) |  |
| Unaffiliated issuers | &nbsp;&nbsp; $60883741 |
| Affiliated issuers | &nbsp;&nbsp; (303)<br>|
| Futures contracts | &nbsp;&nbsp; (350284)<br>|
| Foreign currency | &nbsp;&nbsp; (4027)<br>|
| Net realized gain (loss)  | &nbsp;&nbsp; $60529127 |
| Change in unrealized appreciation or depreciation |  |
| Unaffiliated issuers | &nbsp;&nbsp; $15981869 |
| Affiliated issuers | &nbsp;&nbsp; (1991)<br>|
| Futures contracts | &nbsp;&nbsp; 1100856 |
| Translation of assets and liabilities in foreign currencies | &nbsp;&nbsp; 81188 |
| Net unrealized gain (loss) | &nbsp;&nbsp; $17161922 |
| Net realized and unrealized gain (loss) | &nbsp;&nbsp; $77691049 |
| Change in net assets from operations | &nbsp;&nbsp; $102987995 |

---

**See Notes to Financial Statements**

------

MFS Total Return Series

**Financial Statements** \| **Statements of Changes in Net Assets**

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

---

| | | |
|:---|:---|:---|
|  | **Six months ended** | **Year ended** |
|  | <br>**6/30/25** <br>**(unaudited)**<br>| <br>**12/31/24** |
| **Change in net assets** |  |  |
| **From operations** |  |  |
| Net investment income (loss) | $25296946 | &nbsp;&nbsp; $52373039 |
| Net realized gain (loss) | 60529127 | &nbsp;&nbsp; 159535247 |
| Net unrealized gain (loss) | 17161922 | &nbsp;&nbsp; (51146751)<br>|
| Change in net assets from operations | $102987995 | &nbsp;&nbsp; $160761535 |
| Total distributions to shareholders | $— | &nbsp;&nbsp; $(156595673)<br>|
| Change in net assets from fund share transactions | $(121037156)<br>| &nbsp;&nbsp; $(89646072)<br>|
| Total change in net assets | $(18049161)<br>| &nbsp;&nbsp; $(85480210)<br>|
| **Net assets** |  |  |
| At beginning of period | 2098596158 | &nbsp;&nbsp; 2184076368 |
| At end of period | $2080546997 | &nbsp;&nbsp; $2098596158 |

---

**See Notes to Financial Statements**

------

MFS Total Return Series

**Financial Statements** \| **Financial Highlights**

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Initial Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $23.27 | &nbsp;&nbsp; $23.26 | &nbsp;&nbsp; $22.49 | &nbsp;&nbsp; $27.78 | &nbsp;&nbsp; $26.02 | &nbsp;&nbsp; $24.90 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.30 | &nbsp;&nbsp; $0.61 | &nbsp;&nbsp; $0.55 | &nbsp;&nbsp; $0.45 | &nbsp;&nbsp; $0.39 | &nbsp;&nbsp; $0.47 |
| Net realized and unrealized gain (loss) | 0.90 | &nbsp;&nbsp;&nbsp;&nbsp;1.19 | &nbsp;&nbsp;&nbsp;&nbsp;1.69 | &nbsp;&nbsp; (3.10)<br>| &nbsp;&nbsp;&nbsp;&nbsp;3.24 | &nbsp;&nbsp;&nbsp;&nbsp;1.88 |
| Total from investment operations | $1.20 | &nbsp;&nbsp; $1.80 | &nbsp;&nbsp; $2.24 | &nbsp;&nbsp; $(2.65)<br>| &nbsp;&nbsp; $3.63 | &nbsp;&nbsp; $2.35 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.61)<br>| &nbsp;&nbsp; $(0.48)<br>| &nbsp;&nbsp; $(0.44)<br>| &nbsp;&nbsp; $(0.51)<br>| &nbsp;&nbsp; $(0.57)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.18)<br>| &nbsp;&nbsp; (0.99)<br>| &nbsp;&nbsp; (2.20)<br>| &nbsp;&nbsp; (1.36)<br>| &nbsp;&nbsp; (0.66)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.79)<br>| &nbsp;&nbsp; $(1.47)<br>| &nbsp;&nbsp; $(2.64)<br>| &nbsp;&nbsp; $(1.87)<br>| &nbsp;&nbsp; $(1.23)<br>|
| Net asset value, end of period (x) | $24.47 | &nbsp;&nbsp; $23.27 | &nbsp;&nbsp; $23.26 | &nbsp;&nbsp; $22.49 | &nbsp;&nbsp; $27.78 | &nbsp;&nbsp; $26.02 |
| Total return (%) (k)(r)(s)(x) | 5.16<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;7.75 | &nbsp;&nbsp;&nbsp;&nbsp;10.44 | &nbsp;&nbsp; (9.58)<br>| &nbsp;&nbsp;&nbsp;&nbsp;14.12 | &nbsp;&nbsp;&nbsp;&nbsp;9.81 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.71<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.71 | &nbsp;&nbsp;&nbsp;&nbsp;0.71 | &nbsp;&nbsp;&nbsp;&nbsp;0.71 | &nbsp;&nbsp;&nbsp;&nbsp;0.70 | &nbsp;&nbsp;&nbsp;&nbsp;0.71 |
| Expenses after expense reductions | 0.61<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.61 | &nbsp;&nbsp;&nbsp;&nbsp;0.61 | &nbsp;&nbsp;&nbsp;&nbsp;0.61 | &nbsp;&nbsp;&nbsp;&nbsp;0.61 | &nbsp;&nbsp;&nbsp;&nbsp;0.61 |
| Net investment income (loss) | 2.60<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;2.54 | &nbsp;&nbsp;&nbsp;&nbsp;2.45 | &nbsp;&nbsp;&nbsp;&nbsp;1.84 | &nbsp;&nbsp;&nbsp;&nbsp;1.43 | &nbsp;&nbsp;&nbsp;&nbsp;1.95 |
| Portfolio turnover rate | 21<br> (n)<br>| &nbsp;&nbsp; 58 | &nbsp;&nbsp; 38 | &nbsp;&nbsp; 67 | &nbsp;&nbsp; 98 | &nbsp;&nbsp; 84 |
| Net assets at end of period (000 omitted) | $944292 | &nbsp;&nbsp; $960389 | &nbsp;&nbsp; $1000723 | &nbsp;&nbsp; $1001860 | &nbsp;&nbsp; $1274331 | &nbsp;&nbsp; $1219438 |

---

**See Notes to Financial Statements**

------

MFS Total Return Series

*Financial Highlights - continued*

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Service Class**  | **Six months** <br>**ended**<br>| **Year ended** | **Year ended** | **Year ended** | **Year ended** | **Year ended** |
|  | **6/30/25** <br>**(unaudited)**<br>| **12/31/24** | **12/31/23** | **12/31/22** | **12/31/21** | **12/31/20** |
| Net asset value, beginning of period | $22.64 | &nbsp;&nbsp; $22.68 | &nbsp;&nbsp; $21.95 | &nbsp;&nbsp; $27.18 | &nbsp;&nbsp; $25.50 | &nbsp;&nbsp; $24.43 |
| **Income (loss) from investment operations** |  |  |  |  |  |  |
| Net investment income (loss) (d) | $0.27 | &nbsp;&nbsp; $0.53 | &nbsp;&nbsp; $0.49 | &nbsp;&nbsp; $0.38 | &nbsp;&nbsp; $0.32 | &nbsp;&nbsp; $0.40 |
| Net realized and unrealized gain (loss) | 0.87 | &nbsp;&nbsp;&nbsp;&nbsp;1.16 | &nbsp;&nbsp;&nbsp;&nbsp;1.65 | &nbsp;&nbsp; (3.04)<br>| &nbsp;&nbsp;&nbsp;&nbsp;3.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.83 |
| Total from investment operations | $1.14 | &nbsp;&nbsp; $1.69 | &nbsp;&nbsp; $2.14 | &nbsp;&nbsp; $(2.66)<br>| &nbsp;&nbsp; $3.49 | &nbsp;&nbsp; $2.23 |
| **Less distributions declared to shareholders** |  |  |  |  |  |  |
| From net investment income | $— | &nbsp;&nbsp; $(0.55)<br>| &nbsp;&nbsp; $(0.42)<br>| &nbsp;&nbsp; $(0.37)<br>| &nbsp;&nbsp; $(0.45)<br>| &nbsp;&nbsp; $(0.50)<br>|
| From net realized gain |  | &nbsp;&nbsp; (1.18)<br>| &nbsp;&nbsp; (0.99)<br>| &nbsp;&nbsp; (2.20)<br>| &nbsp;&nbsp; (1.36)<br>| &nbsp;&nbsp; (0.66)<br>|
| Total distributions declared to shareholders | $— | &nbsp;&nbsp; $(1.73)<br>| &nbsp;&nbsp; $(1.41)<br>| &nbsp;&nbsp; $(2.57)<br>| &nbsp;&nbsp; $(1.81)<br>| &nbsp;&nbsp; $(1.16)<br>|
| Net asset value, end of period (x) | $23.78 | &nbsp;&nbsp; $22.64 | &nbsp;&nbsp; $22.68 | &nbsp;&nbsp; $21.95 | &nbsp;&nbsp; $27.18 | &nbsp;&nbsp; $25.50 |
| Total return (%) (k)(r)(s)(x) | 5.04<br> (n)<br>| &nbsp;&nbsp;&nbsp;&nbsp;7.46 | &nbsp;&nbsp;&nbsp;&nbsp;10.22 | &nbsp;&nbsp; (9.84)<br>| &nbsp;&nbsp;&nbsp;&nbsp;13.84 | &nbsp;&nbsp;&nbsp;&nbsp;9.52 |
| **Ratios (%) (to average net assets)** <br>**and Supplemental data:**<br>|  |  |  |  |  |  |
| Expenses before expense reductions | 0.96<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.96 | &nbsp;&nbsp;&nbsp;&nbsp;0.96 | &nbsp;&nbsp;&nbsp;&nbsp;0.96 | &nbsp;&nbsp;&nbsp;&nbsp;0.95 | &nbsp;&nbsp;&nbsp;&nbsp;0.96 |
| Expenses after expense reductions | 0.86<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;0.86 | &nbsp;&nbsp;&nbsp;&nbsp;0.86 | &nbsp;&nbsp;&nbsp;&nbsp;0.86 | &nbsp;&nbsp;&nbsp;&nbsp;0.86 | &nbsp;&nbsp;&nbsp;&nbsp;0.86 |
| Net investment income (loss) | 2.35<br> (a)<br>| &nbsp;&nbsp;&nbsp;&nbsp;2.29 | &nbsp;&nbsp;&nbsp;&nbsp;2.20 | &nbsp;&nbsp;&nbsp;&nbsp;1.60 | &nbsp;&nbsp;&nbsp;&nbsp;1.17 | &nbsp;&nbsp;&nbsp;&nbsp;1.71 |
| Portfolio turnover rate | 21<br> (n)<br>| &nbsp;&nbsp; 58 | &nbsp;&nbsp; 38 | &nbsp;&nbsp; 67 | &nbsp;&nbsp; 98 | &nbsp;&nbsp; 84 |
| Net assets at end of period (000 omitted) | $1136255 | &nbsp;&nbsp; $1138208 | &nbsp;&nbsp; $1183353 | &nbsp;&nbsp; $1179835 | &nbsp;&nbsp; $1407467 | &nbsp;&nbsp; $1319320 |

---

&nbsp;&nbsp;&nbsp;&nbsp;(a) Annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(d) Per share data is based on average shares outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;(k) The total return does not reflect expenses that apply to separate accounts. Inclusion
 of these charges would reduce the total return figures for all periods shown.

&nbsp;&nbsp;&nbsp;&nbsp;(n) Not annualized.

&nbsp;&nbsp;&nbsp;&nbsp;(r) Certain expenses have been reduced without which performance would have been lower.

&nbsp;&nbsp;&nbsp;&nbsp;(s) From time to time the fund may receive proceeds from litigation settlements, without
 which performance would be lower.

&nbsp;&nbsp;&nbsp;&nbsp;(x) The net asset values and total returns have been calculated on net assets which include
 adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

**See Notes to Financial Statements**

------

MFS Total Return Series

**Notes to Financial Statements (unaudited)**

**(1) Business and Organization**

MFS Total Return Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. The shareholders of each series of the trust are separate accounts of insurance companies, which offer variable annuity and/or life insurance products, and qualified retirement and pension plans.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

**(2) Significant Accounting Policies**

**General** — The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

An operating segment is defined in FASB Accounting Standards Codification Topic 280-Segment Reporting as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the entity's chief operating decision maker (CODM) in making resource allocation decisions and assessing segment performance, and for which discrete financial information is available. The fund represents a single operating segment and the Chairman's Committee of the fund's adviser acts as the segment's CODM. The fund's total returns, expense ratios, and changes in net assets which are used by the CODM to assess segment performance and to make resource allocation decisions to the segment are consistent with that presented within the fund's financial statements.

**Balance Sheet Offsetting** — The fund's accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement, or similar agreement, does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund's Significant Accounting Policies note under the captions for each of the fund's in-scope financial instruments and transactions.

**Investment Valuations** — Subject to its oversight, the fund's Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS as the fund's adviser, pursuant to the fund's valuation policy and procedures which have been adopted by the adviser and approved by the Board. In accordance with Rule 2a-5 under the Investment Company Act of 1940, the Board of Trustees designated the adviser as the "valuation designee" of the fund. If the adviser, as valuation designee, determines that reliable market quotations are not readily available for an investment, the investment is valued at fair value as determined in good faith by the adviser in accordance with the adviser's fair valuation policy and procedures.

Under the fund's valuation policy and procedures, equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing service. Debt instruments and floating rate loans, including restricted debt instruments, are generally valued at an evaluated or composite bid as provided by a third-party pricing service. Debt instruments sold short are generally valued at an evaluated or composite mean as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Futures contracts are generally valued at last posted settlement price on their primary exchange as provided by a third-party pricing service. Futures contracts for which there were no trades that day for a particular position are generally valued at the closing bid quotation on their primary exchange as provided by a third-party pricing service. Open-end investment companies are generally valued at net asset value per share. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

Under the fund's valuation policy and procedures, market quotations are not considered to be readily available for debt instruments, floating rate loans, and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services or otherwise determined by the adviser in accordance with the adviser's fair valuation policy and

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

procedures. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, spreads and other market data. Pricing services generally value debt instruments assuming orderly transactions of institutional round lot sizes, but a fund may hold or transact in such securities in smaller, odd lot sizes. In instances where a fund holds an odd lot size position in a debt instrument, such position will typically be valued using the pricing agent's institutional round lot price for the debt instrument. Odd lots may trade at lower prices than institutional round lots, and the fund may receive different prices when it sells odd lot positions than it would receive for sales of institutional round lot positions. An investment may also be valued at fair value if the adviser determines that the investment's value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund's net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund's foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund's net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund's net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund's assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes significant unobservable inputs, which may include the adviser's own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments, such as futures contracts. The following is a summary of the levels used as of June 30, 2025 in valuing the fund's assets and liabilities:

---

| | | | | |
|:---|:---|:---|:---|:---|
| **Financial Instruments** | **Level 1** | **Level 2** | **Level 3** | **Total** |
| Equity Securities | $1271232024 | $— | $— | $1271232024 |
| U.S. Treasury Bonds & U.S. Government <br> Agencies & Equivalents<br>|  | 187697545 |  | 187697545 |
| Non - U.S. Sovereign Debt |  | 671201 |  | 671201 |
| Municipal Bonds |  | 10518904 |  | 10518904 |
| U.S. Corporate Bonds |  | 174008582 |  | 174008582 |
| Residential Mortgage-Backed Securities |  | 219951782 |  | 219951782 |
| Commercial Mortgage-Backed Securities |  | 31066440 |  | 31066440 |
| Asset-Backed Securities (including CDOs) |  | 83459712 |  | 83459712 |
| Foreign Bonds |  | 78603345 |  | 78603345 |
| Investment Companies | 27083558 |  |  | 27083558 |
| Total | $1298315582 | $785977511 | $— | $2084293093 |

---

---

| | | | |
|:---|:---|:---|:---|
| **Other Financial Instruments** |  |  |  |
| Futures Contracts – Assets | $848648 | $— | $848648 |

---

For further information regarding security characteristics, see the Portfolio of Investments.

**Foreign Currency Translation** — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

**Derivatives** — The fund uses derivatives primarily to increase or decrease exposure to a particular market or segment of the market, or security, to increase or decrease interest rate or currency exposure, or as alternatives to direct investments. Derivatives are used for hedging or non-hedging purposes. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. When the fund uses derivatives as an investment to increase market exposure, or for hedging purposes, gains and losses from derivative instruments may be substantially greater than the derivative's original cost.

The derivative instruments used by the fund during the period were futures contracts. Depending on the type of derivative, a fund may exit a derivative position by entering into an offsetting transaction with a counterparty or exchange, negotiating an agreement with the derivative counterparty, or novating the position to a third party. The fund may be unable to promptly close out a futures position in instances where the daily fluctuation in the price for that type of future exceeds the daily limit set by the exchange. The fund's period end derivatives, as presented in the Portfolio of Investments and the associated Derivative Contract tables, generally are indicative of the volume of its derivative activity during the period.

The following table presents, by major type of derivative contract, the fair value, on a gross basis, of the asset and liability components of derivatives held by the fund at June 30, 2025 as reported in the Statement of Assets and Liabilities:

---

| | | |
|:---|:---|:---|
|  |  | **Fair Value (a)** |
| **Risk** | **Derivative Contracts** | **Asset Derivatives** |
| Interest Rate | Futures Contracts | $848648 |

---

(a) Values presented in this table for futures contracts correspond to the values reported in the Portfolio of Investments. Only the current day net variation margin for futures contracts is reported separately within the Statement of Assets and Liabilities.

The following table presents, by major type of derivative contract, the realized gain (loss) on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Futures** <br>**Contracts**<br>|
| Interest Rate | $(350284)<br>|

---

The following table presents, by major type of derivative contract, the change in unrealized appreciation or depreciation on derivatives held by the fund for the six months ended June 30, 2025 as reported in the Statement of Operations:

---

| | |
|:---|:---|
| **Risk** | **Futures** <br>**Contracts**<br>|
| Interest Rate | $1100856 |

---

Derivative counterparty credit risk is managed through formal evaluation of the creditworthiness of all potential counterparties. On certain, but not all, uncleared derivatives, the fund attempts to reduce its exposure to counterparty credit risk whenever possible by entering into an ISDA Master Agreement on a bilateral basis. The ISDA Master Agreement gives each party to the agreement the right to terminate all transactions traded under such agreement if there is a specified deterioration in the credit quality of the other party. Upon an event of default or a termination of the ISDA Master Agreement, the non-defaulting party has the right to close out all transactions traded under such agreement and to net amounts owed under each agreement to one net amount payable by one party to the other. This right to close out and net payments across all transactions traded under the ISDA Master Agreement could result in a reduction of the fund's credit risk to such counterparty equal to any amounts payable by the fund under the applicable transactions, if any.

Collateral and margin requirements differ by type of derivative. For exchange-traded and cleared derivatives (e.g., futures contracts, cleared swaps, and exchange-traded options), margin requirements are set by the exchange or clearing broker and the clearing house and collateral, in the form of cash or securities, is posted by the fund directly with the exchange or clearing broker. Collateral terms are counterparty agreement specific for uncleared derivatives (e.g., forward foreign currency exchange contracts, uncleared swap agreements, and uncleared options). Collateral, in the form of cash and securities, is held in segregated accounts with the fund's custodian in connection with these agreements. For derivatives traded under an ISDA Master Agreement, which contains a credit support annex, the collateral requirements are netted across all transactions traded under such counterparty-specific agreement and an amount is posted from one party to the other to collateralize such obligations. Cash that has been segregated or delivered to cover the fund's collateral or margin obligations under derivative contracts, if any, will be reported separately in the Statement of Assets and Liabilities as restricted cash for uncleared derivatives and/or deposits with brokers for exchange-traded or cleared derivatives. Securities pledged as collateral or margin for the same purpose, if any, are noted in the Portfolio of Investments. The fund may be required to make payments of interest on uncovered collateral or margin obligations with the broker. Any such payments are included in "Miscellaneous" expense in the Statement of Operations.

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

**Futures Contracts** — The fund entered into futures contracts which may be used to hedge against or obtain broad market exposure, interest rate exposure, currency exposure, or to manage duration. A futures contract represents a commitment for the future purchase or sale of an asset at a specified price on a specified date.

Upon entering into a futures contract, the fund is required to deposit with the broker, either in cash or securities, an initial margin in an amount equal to a specified percentage of the notional amount of the contract. Subsequent payments (variation margin) are made or received by the fund each day, depending on the daily fluctuations in the value of the contract, and are recorded for financial statement purposes as unrealized gain or loss by the fund until the contract is closed or expires at which point the gain or loss on futures contracts is realized.

The fund bears the risk of interest rates, exchange rates or securities prices moving unexpectedly, in which case, the fund may not achieve the anticipated benefits of the futures contracts and may realize a loss. While futures contracts may present less counterparty risk to the fund since the contracts are exchange traded and the exchange's clearinghouse guarantees payments to the broker, there is still counterparty credit risk due to the insolvency of the broker. The fund's maximum risk of loss due to counterparty credit risk is equal to the margin posted by the fund to the broker plus any gains or minus any losses on the outstanding futures contracts.

**Mortgage-Backed/Asset-Backed Securities** — The fund invests a significant portion of its assets in asset-backed and/or mortgage-backed securities. For these securities, the value of the debt instrument also depends on the credit quality and adequacy of the underlying assets or collateral as well as whether there is a security interest in the underlying assets or collateral. Enforcing rights, if any, against the underlying assets or collateral may be difficult. U.S. Government securities not supported as to the payment of principal or interest by the U.S. Treasury, such as those issued by Fannie Mae, Freddie Mac, and the Federal Home Loan Banks, are subject to greater credit risk than are U.S. Government securities supported by the U.S. Treasury, such as those issued by Ginnie Mae.

**Security Loans** — Under its Securities Lending Agency Agreement with the fund, Goldman Sachs Agency Lending, as lending agent, loans the securities of the fund to certain qualified institutions (the "Borrowers") approved by the fund. Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returned within the earlier of the standard trade settlement period for such securities or within five business days. The loans are collateralized by cash and/or U.S. government securities in an amount typically at least equal to the market value of the securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of the loaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund on the next business day. The lending agent provides the fund with indemnification against Borrower default. In the event of Borrower default, the lending agent will, for the benefit of the fund, either purchase securities identical to those loaned or pay the fund the market value of the loaned securities. In return, the lending agent assumes the fund's rights to the related collateral. If the collateral value is less than the cost to purchase identical securities or the cash needed to pay their market value, the lending agent is responsible for the shortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment for which the fund bears the risk of loss. A portion of the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated between the fund and the lending agent. On loans collateralized by U.S. government securities, a fee is received from the Borrower, and is allocated between the fund and the lending agent. Income from securities lending is separately reported in the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the same manner as other dividend and interest income. At June 30, 2025, there were no securities on loan or collateral outstanding.

**Indemnifications** — Under the fund's organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund's maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

**Investment Transactions and Income** — Interest income is recorded on the accrual basis. All premium and discount is amortized or accreted for financial statement purposes in accordance with U.S. generally accepted accounting principles. Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend and interest payments received in additional securities are recorded on the ex-dividend or ex-interest date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

Investment transactions are recorded on the trade date. In determining the net gain or loss on securities sold, the cost of securities is determined on the identified cost basis.

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

The fund may purchase or sell mortgage-backed securities on a To Be Announced ("TBA") basis. A TBA transaction is subject to extended settlement and typically does not designate the actual security to be delivered, but instead includes an approximate principal amount. The price of the TBA security and the date that it will be settled are fixed at the time the transaction is negotiated. The value of the security varies with market fluctuations and no interest accrues to the fund until settlement takes place. TBA purchase and sale commitments are held at carrying amount, which approximates fair value and are categorized as level 2 within the fair value hierarchy and included in TBA purchase and TBA sale commitments in the Statement of Assets and Liabilities, as applicable. Losses may arise as a result of changes in the value of the TBA investment prior to settlement date or due to counterparty non-performance.

The fund may also enter into mortgage dollar rolls, typically TBA dollar rolls, in which the fund sells TBA mortgage-backed securities to financial institutions and simultaneously agrees to repurchase similar (same issuer, type and coupon) securities at a later date at an agreed-upon price. During the period between the sale and repurchase, the fund will not be entitled to receive interest and principal payments on the securities sold. The fund accounts for dollar roll transactions as purchases and sales and realizes gains and losses on these transactions. Dollar roll transactions involve the risk that the market value of the securities that the fund is required to purchase may decline below the agreed upon repurchase price of those securities.

The fund may purchase or sell securities on a when-issued or delayed delivery basis. In these extended settlement transactions, the receipt or delivery of the securities by the fund and related payments occur at a future date, usually beyond the customary settlement period. The price of such security and the date that the security will be settled are generally fixed at the time the transaction is negotiated. The value of the security varies with market fluctuations and for debt securities no interest accrues to the fund until settlement takes place. When the fund sells securities on a when-issued or delayed delivery basis, the fund typically owns or has the right to acquire securities equivalent in kind and amount to the securities sold. Purchase and sale commitments for when-issued or delayed delivery securities are held at carrying amount, which approximates fair value and are categorized as level 2 within the fair value hierarchy, and included in When-issued investments purchased and When-issued investments sold in the Statement of Assets and Liabilities, as applicable. Losses may arise due to changes in the value of the underlying securities prior to settlement date or if the counterparty does not perform under the contract's terms, or if the issuer does not issue the securities.

To mitigate the counterparty credit risk on To Be Announced ("TBA") transactions, mortgage dollar rolls, and other types of forward settling mortgage-backed and asset-backed security transactions, the fund whenever possible enters into a Master Securities Forward Transaction Agreement ("MSFTA") on a bilateral basis with each of the counterparties with whom it undertakes a significant volume of transactions. The MSFTA gives each party to the agreement the right to terminate all transactions traded under such agreement if there is a specified deterioration in the credit quality of the other party. Upon an event of default or a termination of the MSFTA, the non-defaulting party has the right to close out all transactions traded under such agreement and to net amounts owed under each transaction to one net amount payable by one party to the other. This right to close out and net payments across all transactions traded under the MSFTA could result in a reduction of the fund's credit risk to such counterparty equal to any amounts payable by the fund under the applicable transactions, if any.

For mortgage-backed and asset-backed securities traded under a MSFTA, the collateral and margining requirements are contract specific. Collateral amounts across all transactions traded under such agreement are netted and an amount is posted from one party to the other to collateralize such obligations. Cash that has been pledged to cover the fund's collateral or margin obligations under a MSFTA, if any, will be reported separately on the Statement of Assets and Liabilities as restricted cash. Securities pledged as collateral or margin for the same purpose, if any, are noted in the Portfolio of Investments.

**Tax Matters and Distributions** — The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund's federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for generally a three year period. Management has analyzed the fund's tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future.

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

Book/tax differences primarily relate to amortization of premium and accretion of discount of debt securities and wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:

---

| | |
|:---|:---|
|  | &nbsp;&nbsp; **Year ended** <br>**12/31/24**<br>|
| Ordinary income (including any short-term capital gains) | &nbsp;&nbsp; $52312099 |
| Long-term capital gains | &nbsp;&nbsp; 104283574 |
| Total distributions | &nbsp;&nbsp; $156595673 |

---

The federal tax cost and the tax basis components of distributable earnings were as follows:

---

| | |
|:---|:---|
| **As of 6/30/25** |  |
| Cost of investments | &nbsp;&nbsp; $1668416501 |
| Gross appreciation | &nbsp;&nbsp; 503862968 |
| Gross depreciation | &nbsp;&nbsp; (87986376)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; $415876592 |
| <br>**As of 12/31/24** |  |
| Undistributed ordinary income | &nbsp;&nbsp; 61095983 |
| Undistributed long-term capital gain | &nbsp;&nbsp; 144817479 |
| Other temporary differences | &nbsp;&nbsp; (19838)<br>|
| Net unrealized appreciation (depreciation) | &nbsp;&nbsp; 399936866 |

---

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

**Multiple Classes of Shares of Beneficial Interest** — The fund offers multiple classes of shares, which differ in their respective distribution and/or service fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. The fund's distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

---

| | | |
|:---|:---|:---|
|  | **Six months** <br>**ended** <br>**6/30/25**<br>| **Year** <br>**ended** <br>**12/31/24**<br>|
| Initial Class | $— | &nbsp;&nbsp; $71807902 |
| Service Class |  | &nbsp;&nbsp; 84787771 |
| Total | $— | &nbsp;&nbsp; $156595673 |

---

**(3) Transactions with Affiliates**

**Investment Adviser** — The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the following annual rates based on the fund's average daily net assets:

---

| | |
|:---|:---|
| Up to $1 billion | 0.70% |
| In excess of $1 billion and up to $2.5 billion | 0.65% |
| In excess of $2.5 billion and up to $5 billion | 0.55% |
| In excess of $5 billion | 0.50% |

---

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholds agreed to by MFS and the fund's Board of Trustees. MFS has also agreed in writing to waive at least 0.01% of its management fee as part of this agreement. The agreement to waive at least 0.01% of the management fee will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2026. For the six months ended June 30, 2025, this management fee reduction amounted to $142,907, which is included in the reduction of total expenses in the Statement of Operations. The management fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.66% of the fund's average daily net assets.

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

The investment adviser has agreed in writing to pay a portion of the fund's total annual operating expenses, excluding interest, taxes, extraordinary expenses, brokerage and transaction costs, certain tax reclaim recovery expenses (including contingency fees and closing agreement expenses), and investment-related expenses, such that total annual operating expenses do not exceed 0.61% of average daily net assets for the Initial Class shares and 0.86% of average daily net assets for the Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue at least until April 30, 2027. For the six months ended June 30, 2025, this reduction amounted to $870,218, which is included in the reduction of total expenses in the Statement of Operations.

**Distributor** — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. The Trustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of its average daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred by MFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity and variable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of these participating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares as well as shareholder servicing and account maintenance activities. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries. The distribution and/or service fees are computed daily and paid monthly.

**Shareholder Servicing Agent** — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent. For the six months ended June 30, 2025, the fee was $20,945, which equated to 0.0020% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the six months ended June 30, 2025, these costs amounted to $1,417.

**Administrator** — MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services fee is computed daily and paid monthly. The administrative services fee incurred for the six months ended June 30, 2025 was equivalent to an annual effective rate of 0.0137% of the fund's average daily net assets.

**Trustees' and Officers' Compensation** — The fund pays compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. Independent Trustees' compensation is accrued daily and paid subsequent to each Trustee Board meeting. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

**Other** — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

On August 19, 2024, MFS redeemed 3 shares of Service Class for an aggregate amount of $75.

During the six months ended June 30, 2025, pursuant to a policy adopted by the Board of Trustees and designed to comply with Rule 17a-7 under the Investment Company Act of 1940 (the "Act") and relevant guidance, the fund engaged in purchase transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser ("cross-trades") which amounted to $1,491,741.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund's securities trades. This agreement may be rescinded at any time. For the six months ended June 30, 2025, this reimbursement amounted to $5,680, which is included in "Other" income in the Statement of Operations.

**(4) Portfolio Securities**

For the period ended June 30, 2025, purchases and sales of investments, other than short-term obligations, were as follows:

---

| | | |
|:---|:---|:---|
|  | **Purchases** | **Sales** |
| U.S. Government securities | $273839473 | &nbsp;&nbsp; $283081977 |
| Non-U.S. Government securities | 157886052 | &nbsp;&nbsp; 247536347 |

---

------

MFS Total Return Series

*Notes to Financial Statements (unaudited) - continued* 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

**(5) Shares of Beneficial Interest** 

The fund's Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **Six months ended** <br>**6/30/25** | **Six months ended** <br>**6/30/25** | **Year ended** <br>**12/31/24** | **Year ended** <br>**12/31/24** |
|  | **Shares** | **Amount** | **Shares** | **Amount** |
| Shares sold |  |  |  |  |
| Initial Class | 408243 | &nbsp;&nbsp; $9658304 | &nbsp;&nbsp; 854720 | &nbsp;&nbsp; $20353083 |
| Service Class | 1352981 | &nbsp;&nbsp; 31259354 | &nbsp;&nbsp; 2911177 | &nbsp;&nbsp; 67266041 |
|  | 1761224 | &nbsp;&nbsp; $40917658 | &nbsp;&nbsp; 3765897 | &nbsp;&nbsp; $87619124 |
| Shares issued to shareholders <br>in reinvestment of distributions<br>|  |  |  |  |
| Initial Class |  | $— | &nbsp;&nbsp; 3085857 | &nbsp;&nbsp; $71807902 |
| Service Class |  |  | &nbsp;&nbsp; 3741737 | &nbsp;&nbsp; 84787771 |
|  |  | $— | &nbsp;&nbsp; 6827594 | &nbsp;&nbsp; $156595673 |
| Shares reacquired |  |  |  |  |
| Initial Class | (3098712)<br>| &nbsp;&nbsp; $(73290330)<br>| &nbsp;&nbsp; (5688143)<br>| &nbsp;&nbsp; $(135563303)<br>|
| Service Class | (3851910)<br>| &nbsp;&nbsp; (88664484)<br>| &nbsp;&nbsp; (8560888)<br>| &nbsp;&nbsp; (198297566)<br>|
|  | (6950622)<br>| &nbsp;&nbsp; $(161954814)<br>| &nbsp;&nbsp; (14249031)<br>| &nbsp;&nbsp; $(333860869)<br>|
| Net change |  |  |  |  |
| Initial Class | (2690469)<br>| &nbsp;&nbsp; $(63632026)<br>| &nbsp;&nbsp; (1747566)<br>| &nbsp;&nbsp; $(43402318)<br>|
| Service Class | (2498929)<br>| &nbsp;&nbsp; (57405130)<br>| &nbsp;&nbsp; (1907974)<br>| &nbsp;&nbsp; (46243754)<br>|
|  | (5189398)<br>| &nbsp;&nbsp; $(121037156)<br>| &nbsp;&nbsp; (3655540)<br>| &nbsp;&nbsp; $(89646072)<br>|

---

**(6) Line of Credit**

The fund and certain other funds managed by MFS participate in a $1.45 billion unsecured committed line of credit of which $1.2 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the highest of 1) Daily Simple SOFR (Secured Overnight Financing Rate) plus 0.10%, 2) the Federal Funds Effective Rate, or 3) the Overnight Bank Funding Rate, each plus an agreed upon spread. A commitment fee, based on the average daily unused portion of the committed line of credit, is allocated among the participating funds. The line of credit expires on March 12, 2026 unless extended or renewed. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at rates equal to customary reference rates plus an agreed upon spread. For the six months ended June 30, 2025, the fund's commitment fee and interest expense were $4,976 and $0, respectively, and are included in "Miscellaneous" expense in the Statement of Operations.

**(7) Investments in Affiliated Issuers**

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers for the six months ended June 30, 2025:

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Beginning** <br>**Value**<br>| **Purchases** | &nbsp;&nbsp; **Sales** <br>**Proceeds**<br>| &nbsp;&nbsp; **Realized** <br>**Gain** <br>**(Loss)**<br>| &nbsp;&nbsp; **Change in** <br>**Unrealized** <br>**Appreciation** <br> **or** <br>**Depreciation**<br>| &nbsp;&nbsp; **Ending** <br>**Value**<br>|
| MFS Institutional Money Market <br> Portfolio<br>| &nbsp;&nbsp; $22990011 | &nbsp;&nbsp; $202526801 | &nbsp;&nbsp; $198430960 | &nbsp;&nbsp; $(303)<br>| &nbsp;&nbsp; $(1991)<br>| &nbsp;&nbsp; $27083558 |

---

---

| | | |
|:---|:---|:---|
| **Affiliated Issuers** | &nbsp;&nbsp; **Dividend** <br>**Income**<br>| &nbsp;&nbsp; **Capital Gain** <br>**Distributions**<br>|
| MFS Institutional Money Market Portfolio | &nbsp;&nbsp; $185723 | $— |

---

------

**ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Total Return Series.

**ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

There is nothing to report for this item for MFS Total Return Series.

**ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.**

This information is disclosed as part of the financial statements included in Item 7 above for MFS Total Return Series. See the Statement of Operations and Note 3 within the Notes to Financial Statements for more information.

**ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.**

Not Applicable.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 12. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.
Not applicable to the Registrant.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 13. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.
Not applicable to the Registrant.

------

#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 14. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.
Not applicable to the Registrant.

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#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 15. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.
There were no material changes to the procedures by which shareholders may send recommendations to the Board for nominees to the Registrant's Board since the Registrant last provided disclosure as to such procedures in response to the requirements of Item 407 (c)(2)(iv) of Regulation S-K or this Item.

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#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 16. CONTROLS AND PROCEDURES.
* Based upon their evaluation of the effectiveness of the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940 (the "Act")) as conducted within 90 days of the filing date of this report on Form N-CSR, the Registrant's principal financial officer and principal executive officer have concluded that those disclosure controls and procedures provide reasonable assurance that the material information required to be disclosed by the Registrant on this report is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission's rules and forms. 

* There were no changes in the Registrant's internal controls over financial reporting (as defined in Rule 30a-3(d) under the Act) that occurred during the period covered by the report that have materially affected, or are reasonably likely to materially affect, the Registrant's internal control over financial reporting. 

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#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 17. DISCLOSURE OF SECURITIES LENDING ACTIVITIES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.
Not applicable to the Registrant.

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#### &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM 18. RECOVERY OF ERRONEOUSLY AWARDED COMPENSATION.
Not applicable to the Registrant.

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#### ITEM 19. EXHIBITS.
* Any code of ethics, or amendment thereto, that is the subject of the disclosure required by Item 2, to the extent that the registrant intends to satisfy the Item 2 requirements through filing of an exhibit: Not applicable.

* Any policy required by the listing standards adopted pursuant to Rule 10D-1 under the Exchange Act (17 CFR 240.10D-1) by the registered national securities exchange or registered national securities association upon which the registrant's securities are listed. Not applicable.

* A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2): Attached hereto as [EX-99.302CERT](99.302CERT.htm).

* Any written solicitation to purchase securities under Rule 23c-1 under the Act (17 CFR 270.23c-1) sent or given during the period covered by the report by or on behalf of the registrant to 10 or more persons. Not applicable.

* Change in the registrant's independent public accountant. Not applicable.

* If the report is filed under Section 13(a) or 15(d) of the Exchange Act, provide the certifications required by Rule 30a-2(b) under the Act (17 CFR 270.30a-2(b)), Rule 13a-14(b) or Rule 15d-14(b) under the Exchange Act (17 CFR 240.13a-14(b) or 240.15d-14(b)) and Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. 1350) as an exhibit. A certification furnished pursuant to this paragraph will not be deemed "filed" for the purposes of Section 18 of the Exchange Act (15 U.S.C. 78r), or otherwise subject to the liability of that section. Such certification will not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act, except to the extent that the registrant specifically incorporates it by reference. Attached hereto as [EX-99.906CERT](99.906CERT.htm).

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#### Notice
A copy of the Amended and Restated Declaration of Trust, as amended, of the Registrant is on file with the Secretary of State of The Commonwealth of Massachusetts and notice is hereby given that this instrument is executed on behalf of the Registrant by an officer of the Registrant as an officer and not individually and the obligations of or arising out of this instrument are not binding upon any of the Trustees or shareholders individually, but are binding only upon the assets and property of the respective constituent series of the Registrant.

#### SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant) MFS VARIABLE INSURANCE TRUST

By (Signature and Title)\*

/S/ DAVID L. DILORENZO

David L. DiLorenzo, President

Date: August 15, 2025

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)\*

/S/ DAVID L. DILORENZO

David L. DiLorenzo, President (Principal Executive Officer)

Date: August 15, 2025

By (Signature and Title)\*

/S/ KASEY L. PHILLIPS&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

Kasey L. Phillips, Treasurer (Principal Financial Officer and Accounting Officer)

Date: August 15, 2025

\* Print name and title of each signing officer under his or her signature.

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## Ex-99.Cert

**<u>EX-99.302CERT</u>**

**MFS VARIABLE INSURANCE TRUST**

**Certification Pursuant to Section 302 of the Sarbanes-Oxley Act**

I, David L. DiLorenzo, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.I have reviewed this report on Form N-CSR of MFS Variable Insurance Trust;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c.Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of a date within 90 days prior to the filing date of this report based on such evaluation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d.Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the period covered by the report that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.The registrant's other certifying officer and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: August 15, 2025

<u>/S/ DAVID L. DILORENZO</u>

David L. DiLorenzo

President (Principal Executive Officer)

**<u>EX-99.302CERT</u>**

**MFS VARIABLE INSURANCE TRUST**

**Certification Pursuant to Section 302 of the Sarbanes-Oxley Act**

I, Kasey L. Phillips, certify that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.I have reviewed this report on Form N-CSR of MFS Variable Insurance Trust;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4.The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c.Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of a date within 90 days prior to the filing date of this report based on such evaluation; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d.Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the period covered by the report that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5.The registrant's other certifying officer and I have disclosed to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize, and report financial information; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: August 15, 2025

<u>/S/ KASEY L. PHILLIPS</u>

Kasey L. Phillips

Treasurer (Principal Financial Officer and Accounting Officer)

------

## Exhibit 99.906

**<u>EX-99.906CERT</u>**

**MFS VARIABLE INSURANCE TRUST**

**Certification Pursuant to Section 906 of the Sarbanes-Oxley Act**

I, David L. DiLorenzo, certify that, to my knowledge:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.The Form N-CSR (the "Report") of MFS Variable Insurance Trust (the "Registrant") fully complies for the period covered by the Report with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: August 15, 2025

<u>/S/ DAVID L. DILORENZO</u>

David L. DiLorenzo

President (Principal Executive Officer)

**A signed original of this written statement required by Section 906 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.**

**<u>EX-99.906CERT</u>**

**MFS VARIABLE INSURANCE TRUST**

**Certification Pursuant to Section 906 of the Sarbanes-Oxley Act**

I, Kasey L. Phillips, certify that, to my knowledge:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.The Form N-CSR (the "Report") of MFS Variable Insurance Trust (the "Registrant") fully complies for the period covered by the Report with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: August 15, 2025

<u>/S/ KASEY L. PHILLIPS</u>

Kasey L. Phillips

Treasurer (Principal Financial Officer and Accounting Officer)

**A signed original of this written statement required by Section 906 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.**

------