Fund Evaluator:
MFS Municipal High Income R6 (MMHKX)
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Fund Details
MFS Municipal High Income R6 Overview
MFS Municipal High Income R6 (MMHKX) is an actively managed Municipal Bond High Yield Muni fund. MFS launched the fund in 2017.
The investment seeks total return with an emphasis on high income exempt from federal income tax, but also considering capital appreciation. The fund normally invests the fund’s assets primarily in municipal instruments. It invests, under normal market conditions, at least 80% of its net assets in securities and other investments, the interest on which is exempt from U.S. federal income tax.
About MFS Municipal High Income R6 (MMHKX)
There are 2 members of the management team with an average tenure of 4.88 years: Jason Kosty (2021), Megan Poplowski (2022). Management tenure is more important for actively managed funds than passive index funds.
The fund has 3 primary benchmarks: Bloomberg Municipal TR USD index with a weighting of 100%, Bloomberg Muni HY 2% Issuer Cap TR USD index with a weighting of 50% and Bloomberg Municipal TR USD index with a weighting of 50%. MFS Municipal High Income R6 has 2116 securities in its portfolio. The top 10 holdings constitute 6.1% of the fund’s assets. The fund meets the SEC requirement of being classified as a diversified fund. The fund is not considered to have an ESG focus with its investment selection and management.
MFS Municipal High Income R6 is part of the Fixed Income global asset class and is within the Municipal Bond fund group. MFS Municipal High Income R6 has 3.8% of its portfolio invested in foreign issues. The overall assets allocated to domestic stock is 0.0%. There is 0.0% allocated to foreign stock, and 0.0% is allocated to preferred stocks. The bond allocation as a percentage of total assets is 97.6% (93.8% domestic bond, 3.8% foreign bond and 0.0% convertible bond). MFS Municipal High Income R6 has 2.4% of the portfolio in cash.
Assets Under Management
The fund has $1 billion in total assets, which is above the $803 million average for the High Yield Muni category. Normally, lower assets under management translates to higher average expense ratios, and greater total assets are desired. However, for some investment categories, such as small-cap investing, it may be difficult for the manager to fully employ the desired active strategy if assets grow too large or too quickly.
MMHKX Performance and Fees
The expense ratio measures how much of a fund’s assets are used for administrative expenses and operating expenses, including adviser fees and fees for the transfer agent and custodial services. The MFS Municipal High Income R6 expense ratio is average compared to funds in the High Yield Muni category. MFS Municipal High Income R6 has an expense ratio of 0.57%, which is 42% lower than its category average, making the fund expense ratio grade a A. While it is difficult to predict returns, it is known that high annual expense ratios reduce your rate of return, and excessive fees are difficult to overcome. Active management normally comes with higher expense ratios than passive index management. Certain investment categories such as small company and foreign also normally have higher expense ratios. It is best to compare fund expense ratios against the category averages for meaningful assessments.
High portfolio turnover can translate to higher expenses and lower aftertax returns. MFS Municipal High Income R6 has a portfolio turnover rate of 9%, indicating that holds its assets around 0.1 years. By way of comparison, the average portfolio turnover is 51% for the High Yield Muni category.
Recently, in the month of July 2026, MFS Municipal High Income R6 returned -1.9%, which earned it a grade of C, as the High Yield Muni category had an average return of -1.8%. The letter grades of A, B, C, D and F are based upon relative rankings within the investment category. A grade of A, for example, would indicate that the return is in the highest 20% for that time period compared to all funds in that category.
MFS Municipal High Income R6 has a trailing yield of 4.51%, which is above the 4.46% category average. The fund normally distributes its income monthly.
It’s natural to seek the best-performing investments, but you must consider the relationship between risk and return and the impact of costs and taxes on your realized returns.
MFS Municipal High Income R6 Grades
Year to date, the fund has returned 1.8%, 0.3 percentage points better than the category, which translates into a grade of B. The fund has returned 7.9% over the past year (grade of B), 5.3% over the past three years (grade of A) and 0.6% per year over the past five years (grade of B) and 2.7% per year over the past 10 years (grade of B).
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MMHKX Trailing NAV Total Returns Data as of 7/31/26
| Last Month |
Last Quarter |
Ann'l. 1Yr |
Ann'l. 3Yr |
Ann'l. 5Yr |
Ann'l. 10Yr |
|
| MMHKX Return (NAV) | -1.9% | 0.2% | 7.9% | 5.3% | 0.6% | 2.7% |
| MMHKX Grade | C | C | B | A | B | B |
| +/- Category | -0.1% | 0.1% | 1.1% | 1.2% | 0.4% | 0.2% |
| High Yield Muni Avg | -1.8% | 0.1% | 6.9% | 4.1% | 0.3% | 2.5% |
| MMHKX Tax Cost Ratio | na | na | 0.0% | 0.0% | 0.0% | na |
MMHKX Annual NAV Total ReturnsData as of 7/31/26
| 2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | |
| MMHKX Return (NAV) | 1.8% | 3.6% | 7.3% | 6.2% | -13.8% | 5.3% | 3.6% | 9.7% | 2.0% | 7.7% | 1.8% |
| MMHKX Grade | B | A | A | D | C | C | C | B | B | C | B |
| +/- Category | 0.3% | 1.1% | 2.1% | -0.6% | -0.7% | -0.2% | -0.3% | 0.5% | 0.0% | -0.3% | 0.3% |
| High Yield Muni Avg | 1.5% | 2.5% | 5.2% | 6.8% | -13.1% | 5.5% | 3.8% | 9.2% | 2.0% | 8.0% | 1.5% |
| Risk Measures | |
| Standard Deviation: | 6.8% |
| Total Risk Index: | 0.56 - Below Average |
| Category Risk Index: | 1.04 - Average |
| Category Risk Grade: | C (59% Rank) |
| Beta: | 1.15 |
| R-Squared: | 93% |
| Leveraged Fund: | No |
| Inverse Fund: | No |
| Portfolio Characteristics | |
| Equity Investment Style: | na |
| Bond Investment Style: | na |
| Yield: | 4.5% |
| Dividend Distribution: | Monthly |
| Cap Gains Distribution: | |
| Total Assets: | $5566 Mil |
| Fund Total Assets: | $1,225 Mil |
| Share Class Type: | Retirement |
| Portfolio Turnover: | 9% |
Management Team
| Number of Managers: 2 | |||
| Longest Tenure: 5.3 years | |||
| Average Tenure: 4.9 years | |||
| Managers (Year): Kosty Jason (2021), Poplowski Megan (2022) | |||
Portfolio Composition (as of 6/30/26)
| # of Holdings: | 2116 |
| % in Top 10 Holdings: | 6.1% |
| Fund is Non-Diversified: | No |
| % in Foreign Issues: | 3.8% |
Portfolio Allocation |
|
| Domestic Stock: | 0.0% |
| Foreign Stock: | 0.0% |
| Preferred Stock: | 0.0% |
| Domestic Bond: | 93.8% |
| Foreign Bond: | 3.8% |
| Convertible Bond: | 0.0% |
| Other: | 0.0% |
| Cash: | 2.4% |
Purchase Information
| Fund Family: | MFS |
| Phone Number: | 800-225-2606 |
| Website: | http://www.mfs.com |
| Status: | Open |
| Inception Date: | June 2, 2017 |
| Min. Initial Purchase: | $ 0 |
| Min. Initial IRA Purchase: | $ 0 |
| True No-Load: | Yes |
| Front Load Maximum: | 0.00% |
| Deferred Charge Maximum: | 0.00% |
| Redemption Charge Maximum: | 0.00% |
| 12b-1 Fee: | na |
Expenses and Fees | |
| Expense Ratio (%): | 0.57% ( Rating : Avg ) |
| Category Average Expense Ratio (%): | 0.98% |
| Share Class: | MFS Municipal High Income A |
| Min. Subsequent Purchase: | $ 0 |
| Min. Subsequent IRA Purchase: | $ 0 |
