MFS Municipal Income Fund

S000002536MFS Municipal Series TrustCIK 0000751656

Share classes

7 classes of this one portfolio · 0 exchange-listed

Class ID	Symbol	Status	Security in the master	Type
C000006991	MFIAX	NOT_LISTED	not exchange-listed	—
C000105400	MIMIX	NOT_LISTED	not exchange-listed	—
C000006992	MMIBX	NOT_LISTED	not exchange-listed	—
C000006993	MMICX	NOT_LISTED	not exchange-listed	—
C000042676	MMIDX	NOT_LISTED	not exchange-listed	—
C000042677	MMIGX	NOT_LISTED	not exchange-listed	—
C000194254	MPMNX	NOT_LISTED	not exchange-listed	—

The share-class bridge is a snapshot, not history. The SEC's fund share-class file says what each class trades as today, not what it traded as at a past report date. A fund that changed ticker or converted from a mutual fund resolves to its present-day symbol for every historical month shown.

Share classes

Report period

1 period filed. Holdings below describe the selected month only.

2026-03-31

Filing

NPORT-P · filed 2026-05-26

Report date: 2026-03-31
Net assets: $6,946,353,773.82
Total assets: $7,015,440,885.9
Total liabilities: $69,087,112.08
Assets invested: $0
Cash not reported in C or D: $2,433.78
Amendment: No
Accession: 0002071691-26-011438

By asset category

N-PORT Item C.4.a

DBTDebt$6.66B96.3%

STIVShort-term investment veh…$175.23M2.5%

ABS-MBSAsset-backed: mortgage-ba…$77.17M1.1%

By asset category

By issuer category

N-PORT Item C.4.b

MUNMunicipal$6.69B96.7%

RFRegistered fund$168.42M2.4%

USGSEUS government sponsored e…$32.18M0.5%

CORPCorporate$25.55M0.4%

By issuer category

By investment country

as filed

USUS$6.81B98.6%

PRPR$89.87M1.3%

GUGU$8.20M0.1%

VIVI$1.37M0.0%

By country

Classification look-through

Positions resolved to the master through ISIN, then rolled up through the taxonomy. 0.0% of reported value reaches a classification.

Not resolved to the master(2,292)$6.91B100.0%

Classification covers part of the master. 5,771 of 13,106 active securities are classified. Anything unclassified is shown as its own band rather than dropped, so a look-through total that falls short of 100% is telling you about coverage, not about the fund.

Percentages are of the reported value of positions above ($6.91B), not of the fund’s net assets ($6.95B). The two differ by cash, derivatives filed with no market value, and rounding.

Classification look-through

Holdings

2,292 positions in this filing

Issuer nameAsset categoryIssuer categoryCountry

Issuer↕	In master	CUSIP / ISIN	Asset	Balance↕	Value↕	Weight▼	Country
MFS Institutional Money Market Portfolio MFS Institutional Money Market Portfolio, Cla…	—	55291X109 US55291X1090	STIV RF

1–50 of 2,292

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Balance is meaningless without its unit. N-PORT Item C.2.a says what the balance column counts: shares (NS), principal amount (PA), contracts (NC), or something the filer describes (OU). A bond position read as a share count is off by orders of magnitude. Every balance on this page carries its unit code.

Missing CUSIPs are filed as placeholders. Filers with no CUSIP conventionally write 999999999 or N/A rather than leaving the field blank — 1,187,114 of 5,347,869 positions do. Those are shown as missing here, not as identifiers.