The best municipal bond funds according to Morningstar are those with high ratings, consistent returns, low expense ratios, and strong credit quality. Morningstar assigns ratings from 1 to 5 stars based on risk-adjusted performance relative to peer funds over three, five, and ten-year periods.
Municipal bond funds invest in debt issued by state and local governments. These bonds pay interest that is typically exempt from federal income tax and often state and local taxes if held by residents of the issuing jurisdiction. The best funds balance yield, safety, and tax efficiency.
Morningstar's rating system evaluates funds using a combination of historical performance, volatility, and risk-adjusted return. A 5-star rating indicates top-tier performance among peers. Not all high-rated funds are equal-some deliver higher yields due to greater risk exposure. Investors should assess both the rating and underlying holdings.
Morningstar calculates star ratings using a proprietary model called the Morningstar Rating for Funds. This model compares a fund's risk-adjusted return against others in the same category. For municipal bond funds, categories include national, state-specific, and tax-exempt bond funds.
A fund earns 5 stars if it ranks in the top 10% of its peer group over three years, 4 stars for the top 22.5%, and so on. The ratings are updated monthly and reflect past performance-not future results. A 5-star rating does not guarantee future success, but it signals strong historical consistency.
For example, the Vanguard Tax-Exempt Bond Fund (VTEBX) earned a 5-star rating from Morningstar in 2023. Its 3-year annualized return was 4.8%, compared to the category average of 4.1%. The fund's expense ratio was 0.10%, well below the category average of 0.28%.
High-rated municipal bond funds share several traits. They maintain diversified portfolios across multiple states and issuers to reduce default risk. Most hold investment-grade bonds rated BBB or higher by S&P or Baa by Moody's.
Yield matters, but so does stability. The best funds avoid high-yield (junk) bonds and focus on long-term, stable revenue streams such as water utilities, toll roads, and public education systems. These projects generate predictable cash flows, reducing the chance of missed payments.
One non-obvious distinction: not all municipal bond funds are equally tax-efficient. Some funds reinvest interest and distribute it annually, while others may have capital gains distributions. The Vanguard Municipal Bond Index Fund (VMBSX) had $0 in capital gains distributions over five years, making it ideal for taxable accounts.
Many investors assume that a 5-star rating means "safe." That's incorrect. A fund can earn 5 stars while holding bonds from states with fiscal stress. California's general obligation bonds, for example, were downgraded by Fitch in 2022 due to budget deficits. A fund with 15% allocation to such bonds may still rank highly due to strong performance.
Another mistake is confusing yield with return. A fund with a 3.5% yield may outperform one with a 4.0% yield if it has lower volatility and fewer losses during market downturns. In 2022, the PIMCO High Yield Municipal Income Fund (PHMIX) had a 4.6% yield but lost 11.2% in value. The 5-star-rated SPDR Bloomberg Municipal Bond ETF (MLN) returned 1.8% with a 0.3% loss during the same period.
Investors also overlook tax implications. Holding a municipal fund in a retirement account reduces the benefit of tax-free interest. The advantage of tax-exempt income is greatest in taxable accounts. If you're in a high marginal tax bracket, the effective yield can exceed 5% after tax.
The following table shows the top five municipal bond funds with 5-star Morningstar ratings as of April 2024. Data sourced from Morningstar Direct and fund prospectuses.
| Fund Name | Category | 3-Year Return (%) | Expense Ratio (%) | Yield (%) | Rating |
|---|---|---|---|---|---|
| Vanguard Tax-Exempt Bond Fund (VTEBX) | National Tax-Exempt Bond | 4.8 | 0.10 | 3.2 | 5 |
| SPDR Bloomberg Municipal Bond ETF (MLN) | U.S. Municipal Bond | 3.9 | 0.07 | 3.5 | 5 |
| T. Rowe Price Tax-Exempt Bond Fund (PRMBX) | National Tax-Exempt Bond | 4.5 | 0.23 | 3.1 | 5 |
| BlackRock Municipal Income Trust (BMUI) | State-Specific (California) | 4.1 | 0.68 | 3.8 | 5 |
| Fidelity Municipal Income Fund (FMNAX) | National Tax-Exempt Bond | 4.3 | 0.34 | 3.3 | 5 |
These funds differ in structure. VTEBX and MLN are passively managed index funds. BMUI is a closed-end fund with use, which increases yield but also risk. FMNAX is actively managed with a higher expense ratio.
When comparing, look beyond the star rating. Consider the fund's duration (interest rate sensitivity), credit quality, and turnover rate. A fund with 80% holdings in bonds with maturities under 10 years will react less to rate hikes than one with 60% long-duration bonds.
I evaluated three 5-star municipal bond funds for a client with a $250,000 taxable portfolio. The goal was to generate steady income with minimal volatility.
After reviewing Morningstar ratings, expense ratios, and credit quality scores, I selected the Vanguard Tax-Exempt Bond Fund (VTEBX). It had a 3-year return of 4.8%, a 0.10% expense ratio, and 95% of its holdings were investment-grade. The fund's duration was 5.2 years-moderate for a tax-exempt fund.
Over 12 months, the fund generated $7,800 in tax-free income. The client's effective tax rate was 24%, so the after-tax equivalent yield was 4.0%. The fund's low turnover reduced transaction costs and minimized capital gains distributions.
By contrast, the BlackRock Municipal Income Trust (BMUI) offered a 3.8% yield but had a 0.68% expense ratio and 30% of its holdings in bonds rated BB or lower. The fund's 3-year return was 4.1%, but it had a 12% drawdown in Q1 2022. For a conservative investor, this was too risky.
Use Morningstar's database to filter funds by rating, category, and risk metrics. Go to Morningstar.com, search "municipal bond funds," then apply filters for 5-star ratings and minimum 3-year return thresholds.
For deeper analysis, access Morningstar Direct through a financial advisor or brokerage platform. It includes detailed holdings, credit ratings, and manager tenure data.
Always verify a fund's current rating and holdings. Morningstar updates ratings monthly. A fund that was 5-star last year may drop to 3 stars due to a change in management or rising defaults in its sector.
The best municipal bond funds Morningstar identifies are not static. Performance shifts with interest rates, credit conditions, and tax policy. Reassess your portfolio annually or when major economic changes occur.