# EDGAR Filing Document

**Accession Number:** 0000918571
**File Stem:** 0001741773-25-002754
**Filing Date:** 2025-7
**Character Count:** 5620
**Document Hash:** 71cfb58cdadb492dd0bf768b5c88fdbc
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001741773-25-002754.hdr.sgml**: 20250728

**ACCESSION NUMBER**: 0001741773-25-002754

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 19

**FILED AS OF DATE**: 20250728

**DATE AS OF CHANGE**: 20250728

**EFFECTIVENESS DATE**: 20250728

**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:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-74668
- **FILM NUMBER:** 251153461

**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 Research Series (Series ID: S000002668)

---

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

---

## Series and Classes Contracts Data

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

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

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

![](img_c85a5888d9064f1.jpg)

SUPPLEMENT TO THE PROSPECTUS

*Supplement dated July 28, 2025, to the Prospectus dated April 30, 2025.*

## MFS <sup>®</sup> Research Series
**Effective August 1, 2025, the sub-sections entitled "Fees and Expenses" and "Example" under the main heading entitled "Summary of Key Information" are restated in their entirety as follows:**

#### Fees and Expenses
This table describes the fees and expenses that you may pay when you hold shares of the fund. If the fees and expenses imposed by the insurance company that issued your variable contracts or other eligible investor through which the fund is offered were included, your expenses would be higher.

---

| | | |
|:---|:---|:---|
| **Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):** | **Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):** |  |
|  | **Initial Class** | **Service Class** |
| Management Fee | 0.75% | 0.75% |
| Distribution and/or Service (12b-1) Fees |  | 0.25% |
| Other Expenses | <u>0.04%</u> | <u>0.04%</u> |
| Total Annual Fund Operating Expenses | 0.79% | 1.04% |
| Fee Reductions and/or Expense Reimbursements<sup>1</sup> | <u>(0.05)%</u> | <u>(0.05)%</u> |
| Total Annual Fund Operating Expenses After Fee Reductions and/or Expense Reimbursements | 0.74% | 0.99% |

---

1 Massachusetts Financial Services Company (MFS) has agreed in writing to bear the fund's 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 interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.74% of the class' average daily net assets annually for Initial Class shares and 0.99% of the class' average daily net assets annually for Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least April 30, 2027.

VFR-SUP-I-072825

------

MFS Research Series

#### Example
This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. If the fees and expenses imposed by the insurance company that issued your variable contracts or other eligible investor through which an investment in the fund is made were included, your expenses would be higher.

The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods; your investment has a 5% return each year; and the fund's operating expenses remain the same.

Although your actual costs will likely be higher or lower, under these assumptions your costs would be:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | **1 YEAR** | **3 YEARS** | **5 YEARS** | **10 YEARS** |
| **Initial Class Shares** | $76  | $243  | $430  | $969  |
| **Service Class Shares** | $101  | $322  | $565  | $1263  |

---

**-- End of Supplement Data --**

**Effective August 1, 2025, the fifth paragraph in the sub-section entitled "Investment Adviser" under the main heading entitled "Management of the Fund" is restated in its entirety as follows:**

MFS has agreed in writing to bear the fund's 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 interest and borrowing expenses incurred in connection with the fund's investment activity), such that "Total Annual Fund Operating Expenses" do not exceed 0.74% of the class' average daily net assets annually for Initial Class shares and 0.99% of the class' average daily net assets annually for Service Class shares. This written agreement will continue until modified by the fund's Board of Trustees, but such agreement will continue until at least April 30, 2027.

VFR-SUP-I-072825

------