MRBGX
MFS Total Return Bond Fund
MFS Series Trust IX
Expense ratio1
1.45%
Net assets2
$8.26B
Holdings2
1073
Category
Taxable Bond
2025 return3
6.16%

Investment objective & strategy

As of Aug. 27, 2025 · prospectus

Objective. The funds investment objective is to seek total return with an emphasis on current income, but also considering capital appreciation.

Strategy. MFS (Massachusetts Financial Services Company, the funds investment adviser) normally invests at least 80% of the funds net assets in debt instruments. Debt instruments include corporate bonds, U.S. Government securities, foreign government securities, securitized instruments (including mortgage-backed securities and other asset-backed securities), municipal instruments, and other obligations to repay money borrowed. MFS primarily invests the funds assets in investment grade quality debt instruments, but may also invest the funds assets in below investment grade quality debt instruments. MFS may purchase or sell securities for the fund on a when-issued, delayed delivery, or forward commitment basis where payment and delivery take place at a future settlement date, including mortgage-backed securities purchased or sold in the TBA market. MFS may invest the … MFS (Massachusetts Financial Services Company, the funds investment adviser) normally invests at least 80% of the funds net assets in debt instruments. Debt instruments include corporate bonds, U.S. Government securities, foreign government securities, securitized instruments (including mortgage-backed securities and other asset-backed securities), municipal instruments, and other obligations to repay money borrowed. MFS primarily invests the funds assets in investment grade quality debt instruments, but may also invest the funds assets in below investment grade quality debt instruments. MFS may purchase or sell securities for the fund on a when-issued, delayed delivery, or forward commitment basis where payment and delivery take place at a future settlement date, including mortgage-backed securities purchased or sold in the TBA market. MFS may invest the funds assets in foreign securities. MFS normally invests the fund's assets across different industries and sectors, but MFS may invest a significant percentage of the fund's assets in issuers in a single industry or sector. MFS may invest a significant percentage of the funds assets in a single issuer or a small number of issuers. While MFS may use derivatives for any investment purpose, to the extent MFS uses derivatives, MFS expects to use derivatives primarily to increase or decrease exposure to a particular market, segment of the market, or security, to increase or decrease interest rate exposure, or as alternatives to direct investments. Derivatives include futures, forward contracts, options, and swaps. MFS uses an active bottom-up investment approach to buying and selling investments for the fund. Investments are selected primarily based on fundamental analysis of individual instruments and their issuers. Quantitative screening tools that systematically evaluate instruments may also be considered. In structuring the fund, MFS also considers top-down factors. For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.

Top holdings

As of April 30, 2026 · N-PORT
SecurityTickerValue% of fund
US TREASURY N/B $270.86M 3.28%
US TREASURY N/B $174.24M 2.11%
US TREASURY N/B $168.59M 2.04%
US TREASURY N/B $162.12M 1.96%
MFS Institutional Money Market Portfolio, Class A $126.45M 1.53%
US TREASURY N/B $101.99M 1.23%
US TREASURY N/B $95.27M 1.15%
US TREASURY N/B $93.00M 1.13%
US TREASURY N/B $92.29M 1.12%
FR SD8199 $89.19M 1.08%
View all holdings →

Allocation by sector

As of April 30, 2026 · N-PORT
View portfolio breakdown →

Portfolio moves

Jan 31, 2026 → Apr 30, 2026
Opened
35
Exited
33
Increased
6
Decreased
733
Unchanged
300

How many positions this fund opened, exited, grew, trimmed, or left unchanged between its two most recent N-PORT snapshots — net changes between point-in-time reports, not a trade log.

View portfolio moves →

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Advisers

As of April 30, 2025 · N-CEN
FirmRole
MASSACHUSETTS FINANCIAL SERVICES COMPANY Adviser

Footnotes

  1. Expense ratio as of August 27, 2025, from the fund's prospectus.
  2. Net assets and holdings count as of April 30, 2026, from the fund's N-PORT filing.
  3. Total return for calendar year 2025, before tax and after fund expenses. Computed by compounding the twelve monthly total returns the fund reported in its SEC N-PORT filings for 2025 (the latest prospectus does not yet chart this year).

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