MFS Municipal Income Fund Class B (MMIBX)

Fund Assets	6.68B
Expense Ratio	1.55%
Min. Investment	$1,000
Turnover	12.00%
Dividend (ttm)	0.25
Dividend Yield	3.21%
Dividend Growth	5.41%
Payout Frequency	Monthly
Ex-Dividend Date	Sep 30, 2026

Previous Close	7.69
YTD Return	-3.92%
1-Year Return	-3.21%
5-Year Return	-4.93%
52-Week Low	7.58
52-Week High	8.31
Beta (5Y)	0.08
Holdings	2372
Inception Date	Dec 29, 1986

About MMIBX

MFS Municipal Income Fund Class B is a mutual fund that seeks to provide investors with a total return, emphasizing regular income that is exempt from federal income tax while also considering opportunities for capital appreciation. Primarily, the fund invests in a diverse portfolio of municipal bonds, which are debt securities issued by state and local governments or their agencies. While it focuses on investment-grade bonds, it can also allocate assets to below investment grade securities, aiming to capitalize on relative value opportunities within the municipal bond market. The fund is actively managed by an experienced team that utilizes both quantitative risk analysis and in-depth fundamental research, striving for consistent performance and careful risk management. With over 2,000 holdings and substantial assets under management, it plays a significant role for investors seeking federally tax-advantaged income streams. Dividends are distributed monthly, and the fund aligns its performance to the Bloomberg Municipal Bond Index, a widely followed benchmark representing the U.S. municipal bond market. Established in 1986, the fund’s long operational track record and broad diversification make it a major participant in the municipal fixed-income sector.

• Fund Family: MFS
• Category: Muni National Long
• Performance Rating: Below Average
• Risk Rating: Average
• Stock Exchange: Nasdaq
• Ticker Symbol: MMIBX
• Share Class: B
• Index: Bloomberg Municipal Bond TR

Performance

MMIBX had a total return of -3.21% in the past year, including dividends. Since the fund's inception, the average annual return has been 2.80%.

Equivalent Funds

These are funds that follow the same index from the other major fund companies.

Symbol	Provider	Name	Expense Ratio
FLUVX	Fidelity	Fidelity Advisor Municipal Income M	0.73%
FKISX	Fidelity	Fidelity Advisor Municipal Income C	1.44%
FROGX	Fidelity	Fidelity Advisor Municipal Income I	0.49%
FUENX	Fidelity	Fidelity Flex Municipal Income Fund	n/a
FHIGX	Fidelity	Fidelity Municipal Income Fund	0.43%

Other Share Classes

These are alternative share classes of the same fund, from the same provider.

Symbol	Share Class	Expense Ratio
MPMNX	R6	0.47%
MMIDX	A1	0.54%
MIMIX	I	0.54%
MFIAX	A	0.79%

Dividend History

Ex-Dividend	Amount	Pay Date
Sep 30, 2026	$0.02134	Oct 1, 2026
Aug 31, 2026	$0.02174	Sep 1, 2026
Jul 31, 2026	$0.02098	Aug 3, 2026
Jun 30, 2026	$0.02033	Jul 1, 2026
May 29, 2026	$0.02124	Jun 1, 2026
Apr 30, 2026	$0.02022	May 1, 2026

Data Sources: Tiingo, Twelve Data, and more

Historical data is provided by Tiingo. Delayed stock pricing data is provided by Twelve Data. Several fund data points are also provided by Finnhub.

Last checked:

Oct 15, 2026

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