By Harry Prabandham · Updated September 27, 2026
Investing & Markets
Municipal Bonds: Tax-Exempt Income and Its Trade-Offs
Municipal bonds are loans to state and local governments. Their interest is usually federal tax-free, but price, credit, and call risks remain.
Municipal Bonds: Tax-Exempt Income and Its Trade-Offs
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What is a municipal bond?
- A municipal bond is debt issued by a state, city, school district, or public authority to fund projects like schools, water systems, and transit.
- Buyers lend money in exchange for interest, usually paid twice a year, and repayment of principal at maturity.
- Interest on most munis is excluded from federal income tax under Section 103 of the tax code.
- Defaults have been rare compared with corporate bonds but do happen, as Detroit's 2013 bankruptcy and Puerto Rico's debt crisis showed.
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Full Guide
What is a municipal bond?
- A municipal bond is debt issued by a state, city, school district, or public authority to fund projects like schools, water systems, and transit.
- Buyers lend money in exchange for interest, usually paid twice a year, and repayment of principal at maturity.
- Interest on most munis is excluded from federal income tax under Section 103 of the tax code.
- Defaults have been rare compared with corporate bonds but do happen, as Detroit's 2013 bankruptcy and Puerto Rico's debt crisis showed.
How is muni income taxed?
- Most states exempt interest on their own bonds but tax interest on other states' bonds.
- California residents generally owe no California tax on California munis but do owe it on out-of-state muni interest.
- Interest on some private activity bonds is an alternative minimum tax preference item.
- Tax-exempt interest still counts when figuring taxable Social Security benefits and Medicare IRMAA surcharges.
- Gains from selling a bond or fund are taxable, and bonds bought at a market discount can produce ordinary income.
General obligation vs. revenue bonds
- General obligation bonds are backed by the issuer's taxing power and general credit.
- Revenue bonds are repaid from a specific stream, such as tolls, water fees, airport charges, or hospital revenue.
- If that revenue falls short, revenue bondholders may have no claim on the issuer's general taxes.
- Official statements and ongoing disclosures are free on the MSRB's EMMA website.
When does the tax exemption pay off?
- To compare with a taxable bond, divide the muni yield by one minus your combined marginal tax rate to get a taxable-equivalent yield.
- The exemption is worth the most in high federal and state brackets, such as for top-bracket California residents.
- In lower brackets, Treasuries or taxable bonds can pay more after tax.
- Munis inside an IRA or 401(k) waste the exemption, since those accounts already defer or avoid tax.
What are the risks?
- Interest rate risk: when rates rise, bond prices fall, and longer maturities fall more.
- Credit risk: issuers can be downgraded or default, especially on revenue bonds tied to one project.
- Call risk: many munis can be redeemed early when rates fall, ending the higher income.
- Liquidity risk: most individual munis trade infrequently, and small lots can be costly to sell before maturity.
Individual bonds versus funds
- Individual bonds can be held to maturity and chosen from in-state issuers, but diversifying takes research and meaningful size.
- Mutual funds and ETFs offer diversification and daily liquidity but have no maturity date, so share prices move with rates.
- Funds pass tax-exempt interest through, while their capital-gain distributions remain taxable.
- Single-state funds add state tax exemption at the cost of concentrating credit exposure in one state.
Key takeaways
- Muni interest is usually federal tax-free, and often state tax-free for in-state bonds.
- The value depends on your bracket, so compare after-tax yields before assuming munis come out ahead.
- Munis still carry interest rate, credit, call, and liquidity risk.
- Confirm state tax, AMT, and Social Security interactions with a CPA.
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