Are Tax-Free Municipal Bonds Really Worth It? Key Considerations

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Tax-free municipal bonds are worth it mainly for investors in higher tax brackets, and only after you compare their after-tax yield with taxable alternatives. Interest on most municipal bonds (“munis”) is exempt from federal income tax. Bonds issued in your own state may also be exempt from state and local tax. That exemption is the whole case for them. Munis generally pay lower coupons than comparable corporate bonds, so an investor in a low bracket can end up with less income after tax than a plain taxable bond would deliver.

What a municipal bond is

A municipal bond is a loan to a state, city, county or another public entity, such as a school district, transit authority or utility district. The issuer uses the money for day-to-day operations or for a specific project like a bridge, hospital or water system. In return, you receive regular interest payments and get your principal back at maturity.

Munis come in two main forms:

• General obligation (GO) bonds are backed by the issuer’s general taxing power.
• Revenue bonds are repaid from a specific income stream, such as tolls, utility fees or airport charges. Their safety depends on that project’s revenue, not on the issuer’s whole tax base.

Like other bonds, munis are rated for credit quality by agencies such as Moody’s, S&P Global and Fitch Ratings. Ratings of AAA, AA and A indicate an issuer the agency considers financially sound. When a government’s finances weaken, its ratings fall. It then usually has to offer a higher interest rate to attract buyers, so a higher muni yield can signal more risk rather than a better deal.

How the tax exemption actually works

The federal exemption is the main draw: interest on qualifying municipal bonds is excluded from federal taxable income. State treatment varies:

• States with no income tax don’t tax muni interest, because there is no state income tax to begin with.
• Many states exempt their own bonds but tax out-of-state bonds. A resident who buys an out-of-state muni gets the federal exemption but pays state tax on the interest.
• A few states tax some or all muni interest, including bonds from their own issuers in certain cases.

When the issuer is in your state and your state exempts its own bonds, the interest can be free of federal, state and local tax. These bonds are often called “triple tax-free.” This is why single-state muni funds exist, especially for residents of high-tax states like California and New York.

The exemption applies to coupon interest only. Selling a muni for more than you paid, or buying one below face value and holding it to maturity, can create taxable income. Capital gains distributions from a muni fund are also taxable, even though its interest dividends are not.

Running the numbers: tax-equivalent yield

Municipal bonds typically carry lower coupons than similarly rated corporate bonds of comparable maturity. Corporate bonds are generally viewed as riskier, so buyers demand more yield to hold them. To find out whether a muni’s lower yield still comes out ahead, convert it to a tax-equivalent yield (TEY):

TEY = tax-free yield ÷ (1 - tax rate)

The TEY is the yield a taxable bond would need to pay just to match the muni after taxes.

Hypothetical example. Assume a muni yields 3.00% and a comparable taxable corporate bond yields 4.00%. Assume federal tax only, ignoring state tax and any deduction interactions.

If the muni is also exempt from a 5% state tax, a simple approach adds the rates. At a 32% federal rate, the combined 37% gives the same 4.76% TEY. That figure is approximate, because state and federal taxes interact through deductions. Your actual marginal rates, not your average rate, belong in the formula.

The exemption is worth more the higher your marginal rate. A low-bracket investor who buys munis to “avoid taxes” can end up with a lower after-tax return than a taxable bond would have paid. Compare against taxable bonds of similar credit quality and maturity, so you aren’t comparing a AA muni with a lower-rated corporate.

Where “tax-free” stops being tax-free

Social Security benefits

Tax-exempt interest is added back when the IRS determines how much of your Social Security benefits are taxable. Muni interest isn’t taxed directly, but it can push more of your benefits into taxable income. Retirees are some of the most common muni buyers, which makes this one of the biggest traps. It is worth modeling before you shift a large taxable bond position into munis in retirement.

Alternative minimum tax

Interest from certain private activity bonds is a preference item under the alternative minimum tax (AMT). These are munis that finance projects benefiting private parties, such as some airport, housing or stadium bonds. If you are subject to the AMT, that interest can be taxed. Funds and bond listings typically indicate whether a holding is subject to the AMT.

State tax on out-of-state bonds

A national muni fund holds bonds from many states, so if your state taxes out-of-state muni interest, most of the fund’s income may be taxable at the state level. In a high-tax state, that can change which fund or bond is the better buy.

The risks that decide whether munis fit

Interest rate risk

Most munis pay a fixed coupon. When market rates rise, older bonds with lower coupons lose value, because buyers can get better rates on new issues. If you hold to maturity, you still receive full principal. If you need to sell before maturity, you may get less than you paid. The longer the maturity, the larger the effect. A 30-year muni sold after rates have risen can lose a meaningful share of its value.

A rough rule of thumb: price change ≈ -duration × change in yield. Hypothetical: a 1 percentage point rise in yields would cut the price of a bond with a duration of 2 by about 2%, and a bond with a duration of 8 by about 8%. The full mechanics are covered in why bond prices fall when interest rates rise.

Purchasing-power risk

Inflation is the biggest long-term drawback of holding bonds, munis included. You get your dollars back, but they may buy less than when you lent them. A portfolio made up only of low-yielding munis can trail inflation for years. Holding some stocks alongside bonds is the usual way to offset this.

Default risk

Municipal defaults have been rare. Moody’s data covering 1970 to 2022 put the average 10-year cumulative default rate for rated munis at 0.15%. That figure includes lower-rated bonds as well as high-grade ones, and Moody’s recorded a single rated municipal default in 2022. Defaults do happen, though, and they cluster in weaker credits and in revenue bonds tied to a single project. A diversified fund or a portfolio of highly rated bonds lowers the impact of any one failure.

Call risk

Many munis are callable: the issuer can repay principal early and stop paying interest. Issuers usually call bonds after rates have dropped, so they can refinance more cheaply. You get your money back, but you have to reinvest it at the lower rates that made the call attractive. When comparing callable bonds, look at the yield to call as well as the yield to maturity.

Selling before maturity

Individual munis trade over the counter, and many issues trade infrequently. The price you receive depends on the remaining interest payments, prevailing rates on new issues and dealer markups. If you might need the money before maturity, that cost belongs in the comparison.

Short-term tax-free bonds

Short-term munis are a way to get the federal exemption with much less interest rate risk. The options include:

• Municipal notes. Short obligations issued in anticipation of tax receipts (TANs), other revenue (RANs) or a later bond sale (BANs).
• Short-maturity individual munis, including longer bonds that are close to maturity.
• Short-term and ultra-short muni funds and ETFs, which hold portfolios of these securities.

Because they mature soon, their prices move less when rates change. When the yield curve slopes upward, though, they pay less than longer munis. That makes the tax-equivalent comparison tighter, especially against Treasury bills, CDs or high-yield savings, which often serve the same short-horizon purpose. Short-term munis make the most sense for high-bracket investors parking money they will need within a few years.

Other bonds with tax advantages

Munis aren’t the only bonds with a tax break, but the others work differently:

• U.S. Treasury securities (bills, notes, bonds, savings bonds) are taxable federally but exempt from state and local income tax. That can matter as much as the muni exemption in a high-tax state.
• Series EE and I savings bonds can be federally tax-free when used for qualified higher-education expenses and income limits are met.
• Corporate bonds are taxable at the federal and state level. Outside of tax-advantaged accounts, there is no general tax-exempt corporate bond category in the U.S.

One related point: holding munis inside an IRA or 401(k) wastes the exemption. Those accounts already shelter income, and withdrawals from traditional accounts are taxed as ordinary income regardless of the source.

How to buy municipal bonds

There are three main routes:

1. Individual bonds through a brokerage. Online and full-service brokers offer new issues and secondary-market munis. Banks with investment arms do too. Check the rating, maturity, call features, AMT status and the issuer’s state. You can review an issue’s official disclosures and trade history on the MSRB’s EMMA database.
2. Muni mutual funds. Funds pay “exempt-interest dividends” that keep their tax-free character. They offer diversification and professional credit research in exchange for an expense ratio, and capital gains distributions remain taxable.
3. Muni ETFs. These hold similar portfolios and trade on an exchange like stocks, often with lower costs than actively managed funds.

Individual bonds let you hold to maturity and know your cash flows in advance. Funds have no maturity date, so their share price moves with rates indefinitely. A single-state fund adds state tax savings for residents but concentrates credit risk in one economy.

FAQs

The Bottom Line

Municipal bonds suit investors in higher tax brackets who hold bonds in taxable accounts, especially residents of high-tax states who can buy in-state issues. Run the tax-equivalent yield at your actual marginal rate and compare against taxable bonds of similar credit quality and maturity. Retirees should also check how muni interest affects taxation of Social Security benefits, and anyone holding munis in an IRA or 401(k) is giving up the exemption.