Not Always Tax-Free: 7 Municipal Bond Tax Traps

Key Points

  • Although municipal bonds pay interest that is generally exempt from federal and state income taxes, it's not always free from all taxes.
  • We identify some of the taxes that could apply if you buy municipal bonds and next steps you may want to consider.

Investors often think of municipal bonds, which are sold by local and state governments to fund public projects like building new schools and repairing city sewer systems, as being totally tax-free—but that’s not always the case.

While the interest payments on munis are usually exempt from federal income taxes, other taxes may apply. It’s important to know the rules, because municipal bonds are one of the few investments available to income-oriented investors looking to reduce their income tax bills. Here are seven types of taxes that could apply if you buy muni bonds.

1. De minimis tax. The de minimis tax applies to munis that you acquired at a market discount. The de minimis rule says that for bonds purchased at a discount of more than 0.25% for each full year from the time of purchase to maturity, gains resulting from the discount are taxed as ordinary income rather than capital gains. The ordinary income tax rate is generally greater than the capital gains rate, which could result in a greater bite out of your yield.

For example, take a bond that matures in 10 years with a face value of 100. The de minimis “breakpoint” on this bond is 97.5 (100 – [0.25 × 10 years]). If you bought this bond for less than 97.5, you would be required to pay ordinary income tax on the discount.

De minimis thresholds for a $10,000 face value muni

Source: Schwab Center for Financial Research. The example is hypothetical and provided for illustrative purposes only.

What you can do: To avoid the de minimis tax rule, consider purchasing bonds priced at par or at a premium to their face value. Paying a premium may mean having to make adjustments to your tax filing, but the associated tax benefits more than offset the added complication, in our view. In addition, if a bond is selling at a premium, it’s likely because it is offering a high coupon rate.