# EDGAR Filing Document

**Accession Number:** 0000783740
**File Stem:** 0000912938-23-000228
**Filing Date:** 2023-2
**Character Count:** 4477
**Document Hash:** 80e9f9f54c0041cb24dc637b69047cbc
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000912938-23-000228.hdr.sgml**: 20230209

**ACCESSION NUMBER**: 0000912938-23-000228

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20230209

**DATE AS OF CHANGE**: 20230209

**EFFECTIVENESS DATE**: 20230209

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MFS SERIES TRUST X
- **CENTRAL INDEX KEY:** 0000783740
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1130

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-01657
- **FILM NUMBER:** 23601371

**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

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MFS GOVERNMENT MORTGAGE FUND
- **DATE OF NAME CHANGE:** 19930408

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MFS GOVERNMENT INCOME PLUS FUND
- **DATE OF NAME CHANGE:** 19930312

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MASSACHUSETTS MFS GOVERNMENT INCOME PLUS FUND
- **DATE OF NAME CHANGE:** 19921015

## Series and Classes Contracts Data

### MFS Emerging Markets Debt Fund (Series ID: S000002511)

---

|  |  |  |
|:---|:---|:---|
| Class Name | Ticker Symbol | Class ID   |
| A          | MEDAX         | C000006900 |
| B          | MEDBX         | C000006901 |
| C          | MEDCX         | C000006902 |
| I          | MEDIX         | C000006903 |
| R6         | MEDHX         | C000034483 |
| R1         | MEDDX         | C000074224 |
| R2         | MEDEX         | C000074225 |
| R3         | MEDFX         | C000074226 |
| R4         | MEDGX         | C000074227 |

---

## Series and Classes Contracts Data

### MFS Emerging Markets Debt Fund (Series ID: S000002511)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000006900 | A            | MEDAX           |
| C000006901 | B            | MEDBX           |
| C000006902 | C            | MEDCX           |
| C000006903 | I            | MEDIX           |
| C000034483 | R6           | MEDHX           |
| C000074224 | R1           | MEDDX           |
| C000074225 | R2           | MEDEX           |
| C000074226 | R3           | MEDFX           |
| C000074227 | R4           | MEDGX           |

![](image0.jpg)

SUPPLEMENT TO THE PROSPECTUS

*Supplement dated February 9, 2023, to the Prospectus dated November 28, 2022.*

MFS<sup>®</sup> Emerging Markets Debt Fund

------

**Effective immediately, the following is added after the tables in the sections entitled "Portfolio Manager(s)" under the main headings entitled "Summary of Key Information" and "Management of the Fund":**

Effective April 30, 2024, Matt Ryan will no longer be a portfolio manager of the fund.

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