What this line means
Interest income that is exempt from federal income tax — primarily from municipal bonds and municipal bond funds. Even though this interest is not taxed, the IRS still requires you to report it. The amount goes here for informational purposes and can affect other calculations on your return, including Social Security benefit taxation and the Net Investment Income Tax.
Does this apply to you?
- You hold municipal bonds issued by any state or local government
- You own shares in a municipal bond mutual fund or ETF
- You received a 1099-INT or 1099-DIV with an amount in the tax-exempt interest box
- You hold bonds from U.S. territories (Puerto Rico, Guam, USVI) that are federally tax-exempt
Easy to overlook
Tax-exempt interest can make your Social Security benefits taxable Even though muni bond interest is not taxed directly, it is included in the formula that determines how much of your Social Security benefits are taxable. A retiree with significant muni bond income can end up paying tax on up to 85% of their Social Security benefits because of the interest they thought was “tax-free.” 1 IRS Publication 550 — Investment Income and Expenses
Private activity bond interest triggers AMT Interest from certain private activity municipal bonds is tax-exempt for regular income tax but is added back as a preference item for the Alternative Minimum Tax. If you hold private activity bonds and are subject to AMT, this “tax-exempt” interest is effectively taxed. Your 1099-INT Box 9 shows the private activity bond amount. 2 General filing pattern — AMT impact of private activity bond interest
Watch out for this
Not reporting tax-exempt interest at all because it is not taxed. The IRS requires it on your return even though no tax is due on the amount itself. Omitting it can trigger a notice, and more importantly, it understates the income the IRS uses to calculate Social Security taxation, ACA subsidy eligibility, and other income-dependent thresholds.
Footnotes
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IRS Publication 550, Investment Income and Expenses. https://www.irs.gov/pub/irs-pdf/p550.pdf ↩
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IRS Form 1040 Instructions. See also IRS Publication 17, Your Federal Income Tax. https://www.irs.gov/pub/irs-pdf/p17.pdf ↩