MMHKX — MFS Municipal High Income Fund
Data updated: 2026-06-29
MMHKX — MFS Municipal High Income Fund data: holdings, portfolio allocation, expenses, performance, cashflows, risk and SEC filings. Long Municipal - National Bond · $5.40B AUM · 0.57% expense ratio · 6.7% 1-yr return. From SEC regulatory filings.
MMHKX Fund Overview
MMHKX — MFS Municipal High Income Fund is a US mutual fund managed by Mfs Series Trust III, categorised as Long Municipal - National Bond. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.
- Type: US mutual fund
- Manager: Mfs Series Trust III
- Category: Long Municipal - National Bond
- Assets under management: $5.40B
- 1-year return: 6.7%
- Ticker: MMHKX
- SEC CIK: 0000225604
- SEC series ID: S000002429
- Share class ID: C000191232
MMHKX Holdings
Top 10 holdings of MFS Municipal High Income Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.
| Holding | % of net assets |
|---|---|
| MFS Institutional Money Market Portfolio | 2.37% |
| Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue | 1.85% |
| Berks County Municipal Authority (The) | 0.59% |
| Buckeye Tobacco Settlement Financing Authority | 0.58% |
| California Community Choice Financing Authority | 0.50% |
| New York Transportation Development Corp. | 0.46% |
| New Hampshire Business Finance Authority | 0.45% |
| City of Chicago IL | 0.45% |
| New York Transportation Development Corp. | 0.44% |
| Iowa Tobacco Settlement Authority | 0.42% |
MMHKX Portfolio Allocation
Asset-class allocation of MFS Municipal High Income Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Asset class | Allocation |
|---|---|
| Fixed Income | 95.5% |
| Cash & Equivalents | 2.4% |
| Securitized | 0.8% |
MMHKX Performance
Total returns for MMHKX (as of 2026-08-01), from SEC filings.
| Period | Total return |
|---|---|
| YTD | 1.6% |
| 1 year | 6.7% |
| 3 years (annualised) | 5.3% |
| 5 years (annualised) | 1.2% |
MMHKX Risk Information
Risk metrics for MMHKX, derived from monthly returns in SEC filings.
- 1-year volatility (annualised): 4.8%
MMHKX Costs and Fees
MMHKX costs about $57 per $10,000 invested per year in fund expenses.
- Net expense ratio: 0.57%
- Gross expense ratio: 0.65%
- Portfolio turnover: 9%
- Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)
MMHKX Cashflows
Over the 12 months to 2026-04, MFS Municipal High Income Fund had net inflows of $486.80M, from monthly SEC N-PORT filings.
| Month | Net flow |
|---|---|
| 2026-04 | $18.28M |
| 2026-03 | $3.88M |
| 2026-02 | $74.58M |
| 2026-01 | $40.13M |
| 2025-12 | $23.75M |
| 2025-11 | $140.38M |
MMHKX Debt Constituents
Largest debt holdings of MFS Municipal High Income Fund by percentage of net assets, from the latest SEC N-PORT filing.
| Debt holding | % of net assets |
|---|---|
| Puerto Rico Sales Tax Financing Corp. Sales Tax Revenue | 1.85% |
| Berks County Municipal Authority (The) | 0.59% |
| Buckeye Tobacco Settlement Financing Authority | 0.58% |
| California Community Choice Financing Authority | 0.50% |
| New York Transportation Development Corp. | 0.46% |
| New Hampshire Business Finance Authority | 0.45% |
| City of Chicago IL | 0.45% |
| New York Transportation Development Corp. | 0.44% |
| Iowa Tobacco Settlement Authority | 0.42% |
| New Hampshire Business Finance Authority | 0.38% |
MMHKX Prospectus and SEC Filings
Official MFS Municipal High Income Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.
Related Funds
Other Long Municipal - National Bond funds tracked on ABC INVEST:
Data Sources
ABC INVEST compiles this page from public filings made to the U.S. Securities and Exchange Commission (SEC) through EDGAR: portfolio holdings and monthly cashflows from Form N-PORT, expenses and returns from fund prospectuses (Form 485BPOS) and the SEC DERA Risk/Return Summary data sets, annual data from Form N-CEN, and shareholder reports from Form N-CSR.