Are municipal bonds tax exempt? For the most part, yes. Interest paid on bonds issued by states, cities, counties, school districts, and other local government units is excluded from federal income tax under Section 103 of the Internal Revenue Code, and it is often free from state income tax as well.1Office of the Law Revision Counsel. 26 USC 103 – Interest on State and Local Bonds That exemption has real limits, though. Some municipal bonds are taxable by design, some trigger the Alternative Minimum Tax, capital gains from selling a muni are fully taxable, and even the tax-free interest can quietly raise your Medicare premiums and the taxable share of your Social Security benefits.
What the Federal Exemption Actually Covers
Section 103 excludes from gross income the interest paid on bonds issued by a state or any of its political subdivisions. That includes general obligation bonds, which are backed by the issuer’s taxing authority, and revenue bonds, which are repaid from a specific project’s earnings such as tolls, water fees, or hospital charges. The bond has to be issued for a genuine public purpose. Bonds that mostly benefit a private business can lose part or all of the exemption, which is the reason the private activity rules discussed below exist.
The exclusion applies to the interest coupon itself. It does not extend to gains from selling the bond, and it does not automatically extend to every kind of income the bond produces over its life.
State and Local Tax Treatment
Most states exempt interest on bonds issued within their own borders from state and local income tax. Buy a bond issued by your home state or one of its cities and the interest is generally free at both levels. Buy a bond from another state and your home state will usually treat that interest as taxable income.
The pattern is not universal. Illinois, Iowa, Kansas, Oklahoma, and Wisconsin tax interest on at least some of their own municipal bonds. States without an income tax, including Texas, Florida, and Wyoming, do not tax municipal bond interest from any source. Check your own state’s rules before assuming any muni delivers a full state-level exemption.
Triple-Tax-Exempt Territory Bonds
Bonds issued by United States territories are exempt from federal, state, and local income tax no matter where the bondholder lives. That treatment comes from separate federal statutes for each territory, including the provisions covering Puerto Rico under Title 48.2Office of the Law Revision Counsel. 48 USC 745 – Tax Exempt Bonds3Office of the Law Revision Counsel. 48 USC 1423a – Power of Legislature4Office of the Law Revision Counsel. 48 USC 1574 – Legislative Powers and Activities Because the exemption applies in every state, territory bonds are popular with investors who want tax-free income across all levels of government.
When Municipal Bond Interest Is Taxable
Two categories of munis do not deliver a clean federal exemption: private activity bonds and explicitly taxable municipal bonds.
Private Activity Bonds and the AMT
A bond becomes a private activity bond when more than 10 percent of its proceeds are used for a private business purpose and more than 10 percent of the debt service is secured by or derived from that private use. The same label attaches if more than 5 percent of proceeds go to a private business use unrelated to a government purpose, or if the bond finances private loans exceeding the lesser of 5 percent of proceeds or $5 million.5Office of the Law Revision Counsel. 26 USC 141 – Private Activity Bond, Qualified Bond
Many private activity bonds still pay interest that is exempt for regular income tax purposes. The catch is the Alternative Minimum Tax. Interest on specified private activity bonds issued after August 7, 1986, is treated as an AMT preference item and gets added back when calculating alternative minimum taxable income.6Internal Revenue Service. TEB Phase II – Lesson 4 General Rules for Private Activity Bonds The AMT exemption for 2026 is $90,100 for single filers and $140,200 for married couples filing jointly, with phase-outs beginning at $500,000 and $1,000,000 respectively.7Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Most taxpayers will not owe AMT, but a large private activity bond position can push higher earners over the line.
Taxable Municipal Bonds
Some munis are issued as fully taxable from the start because the funded project does not meet the federal test for a public benefit. They pay higher yields to make up for the lost tax advantage. Common examples include:
- Stadiums and arenas used primarily by private professional teams
- Bonds issued to shore up underfunded municipal pension plans
- Convention centers, hotels, and other facilities with significant private commercial use
Because the interest is taxable anyway, these bonds fit reasonably well inside tax-advantaged accounts such as IRAs and 401(k)s, where the interest is not taxed until withdrawal.
Capital Gains Are Never Exempt
The exemption covers interest, not profit on sale. If you sell a municipal bond for more than you paid, the gain is taxable. Bonds held longer than one year produce long-term capital gains taxed at federal rates of 0, 15, or 20 percent depending on your income.8Internal Revenue Service. Topic No. 409, Capital Gains and Losses Bonds sold within one year of purchase produce short-term gains taxed at ordinary income rates, which reach 37 percent in 2026.7Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
Higher-income investors owe an additional 3.8 percent net investment income tax on those gains once modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly). Combined with the top long-term rate, total federal tax on a muni capital gain can reach 23.8 percent. The tax-exempt interest itself is not subject to the net investment income tax; only the gain is.9Internal Revenue Service. Topic No. 559, Net Investment Income Tax
Wash sale rules apply too. Sell a muni at a loss and buy a substantially identical one within 30 days before or after, and the loss is disallowed. The disallowed amount is added to the basis of the replacement bond, deferring rather than eliminating the tax benefit.10Internal Revenue Service. Publication 550, Investment Income and Expenses
The De Minimis Rule on Discount Bonds
Buying a municipal bond on the secondary market for less than face value creates a potential tax bill on the discount, even though the regular coupon interest stays tax-exempt. Whether the discount is taxed as a capital gain or as ordinary income depends on the de minimis threshold.
The threshold equals 0.25 percent times the number of full years remaining until maturity.11Municipal Securities Rulemaking Board. Tax and Liquidity Considerations for Buying Discount Bonds For a bond with 10 years left, that is 2.5 percent of face value. A discount smaller than the threshold is de minimis, and any gain at maturity or sale is taxed at capital gains rates. A discount larger than the threshold is taxed as ordinary income across the whole accrued market discount, a much higher rate for most investors.
Bonds originally sold below face value work differently. If you buy an original issue discount bond in the initial offering at the issue price and hold it to maturity, the accreted discount is treated as tax-exempt interest, not taxable gain.12Municipal Securities Rulemaking Board. About Original Issue Discount Bonds
Tax-Exempt Interest Can Still Cost You
Two indirect effects catch retirees off guard, because both calculations pull tax-exempt interest back into the math.
Social Security Benefits
The IRS uses a figure called combined income to decide how much of your Social Security is taxable. Combined income equals your adjusted gross income, plus tax-exempt interest, plus half of your Social Security benefits. Once combined income tops $25,000 (single) or $32,000 (married filing jointly), up to 85 percent of your benefits become taxable.13Social Security Administration. Must I Pay Taxes on Social Security Benefits? Those thresholds are not adjusted for inflation, so even modest muni interest can push a retiree across them.
Medicare Premium Surcharges
Medicare Part B and Part D premiums carry income-related monthly adjustment amounts, known as IRMAA. The calculation uses modified adjusted gross income, which includes tax-exempt interest. For 2026, surcharges begin above $109,000 (single) or $218,000 (married filing jointly).14Social Security Administration. Medicare Income-Related Monthly Adjustment Amount – Life-Changing Event At the top tier (above $500,000 single or $750,000 joint), the Part B surcharge alone reaches $487 per month per person. Because IRMAA looks at returns from two years earlier, a spike in muni interest today raises premiums in a later year.
Reporting It on Your Return
Tax-exempt interest still has to be reported. The IRS needs the number to run the Social Security and IRMAA calculations, and skipping it can trigger notices even when no tax is due on the amount itself. Report the total on Form 1040, Line 2a.15Internal Revenue Service. Form 1040
Your brokerage sends a Form 1099-INT after year-end with tax-exempt interest in Box 8.16Internal Revenue Service. About Form 1099-INT, Interest Income If you hold private activity bonds, Box 9 shows the interest that has to be reported for AMT purposes; that figure goes on Line 2g of Form 6251.17Internal Revenue Service. Instructions for Form 6251