A municipal bond is a loan you make to a city, county, or state to pay for public projects

When a municipality needs money to build a school, repair roads, or upgrade water systems, it can borrow from the public by issuing bonds. You buy the bond, the municipality borrows your money, and they pay you back with interest over a set period — usually 10 to 30 years. The interest payments are your return on the investment.

The key difference between a municipal bond and a corporate bond is who owes you the money. A corporation issues bonds to fund business operations. A municipality issues bonds to fund public infrastructure. That difference matters for taxes: in most cases, the interest you earn on a municipal bond is not subject to federal income tax, and often not to state or local income tax either.

Municipal bonds are sold through brokers and financial advisors, not directly from the municipality. You can buy them on the secondary market (from other investors) or when they are first issued. The price you pay depends on interest rates, the municipality's credit rating, and how much time is left until the bond matures.

Key Takeaways

  • A municipal bond is a debt security issued by a city, county, or state to raise money for public projects like schools, roads, or water systems.
  • When you buy a municipal bond, you are lending money to the municipality, which pays you back with interest over 10 to 30 years.
  • The interest you earn on most municipal bonds is exempt from federal income tax and often from state and local income taxes as well.
  • Municipal bonds carry credit risk — if the municipality cannot pay, you may not receive your full principal or interest payments.
  • You buy and sell municipal bonds through brokers or financial advisors, not directly from the government.

How the tax exemption works

The federal government does not tax the interest income from most municipal bonds. This is by design: Congress created the tax exemption to make it cheaper for municipalities to borrow money. Lower borrowing costs mean lower taxes or more money for public services.

The exemption applies to bonds issued for public purposes — schools, highways, water treatment, public housing. It does not apply to bonds issued for private purposes, even if a municipality issues them. A bond that finances a private sports stadium or a private business facility, for example, is taxable.

State and local tax exemptions vary. Some states exempt all municipal bond interest from state income tax. Others exempt only bonds issued by municipalities within that state. A few states tax all municipal bond interest. Your tax situation depends on where you live, where the bond was issued, and your income level.

Credit risk and what happens if a municipality defaults

A municipal bond is only as safe as the municipality that issued it. If the city or county cannot pay its debts, it may default — meaning it stops making interest payments or fails to return your principal when the bond matures. This is rare but it happens. Detroit, Stockton, and several other cities have defaulted on bonds in recent decades.

Before you buy a municipal bond, check the municipality's credit rating. Rating agencies like Moody's, Standard & Poor's, and Fitch assign ratings based on the municipality's financial health, tax base, and debt levels. A higher rating means lower risk. Bonds with lower ratings offer higher interest rates to compensate for the higher risk.

If a municipality defaults, bondholders are creditors — they stand in line to be paid after secured creditors but before equity holders. In practice, recovery is often partial and slow. Some municipalities emerge from default and resume payments. Others restructure their debt, which may mean you receive less than you are owed.

General obligation bonds versus revenue bonds

General obligation bonds are backed by the full taxing power of the municipality. If the project funded by the bond does not generate enough revenue, the municipality must raise taxes to pay bondholders. This makes general obligation bonds safer because the municipality has a strong incentive to pay — defaulting would damage its credit rating and make future borrowing expensive.

Revenue bonds are backed only by the revenue from the specific project they finance. A bond that funds a toll road is repaid from toll revenue. A bond that funds a water system is repaid from water fees. If the project does not generate enough revenue, there is no backup source of funds. Revenue bonds carry higher risk and typically offer higher interest rates.

General obligation bonds usually require voter approval before they can be issued. Revenue bonds often do not. This is why you may see revenue bonds used for projects that are less popular or more speculative.

Interest rate risk and market value

When you buy a municipal bond, you lock in an interest rate. If interest rates rise after you buy, new bonds will offer higher rates, and the resale value of your bond will fall. If you need to sell before maturity, you may have to accept a loss.

The longer the bond's maturity, the greater the interest rate risk. A 30-year bond is more sensitive to interest rate changes than a 5-year bond. This is why longer-term bonds typically offer higher interest rates — investors demand compensation for the risk that rates will rise and the bond's value will drop.

If you hold the bond until maturity, interest rate risk does not matter. You will receive your full principal back regardless of what happened to the bond's market price. But if you need to sell early, you may have to sell at a discount.

Call provisions and what they mean for your return

Many municipal bonds include a call provision, which allows the municipality to pay off the bond early — usually after 10 years. If interest rates fall, the municipality can call the bond, pay you back, and issue new bonds at a lower rate. This saves the municipality money but hurts you: you lose the higher interest payments you were counting on.

When a bond is called, you receive your principal back but you cannot reinvest it at the same rate. This is called reinvestment risk. If you bought a bond yielding 5 percent and it gets called when new bonds yield 3 percent, you have lost the opportunity to earn that extra 2 percent for the remaining years.

Call provisions are listed in the bond's official statement. Before you buy, check whether the bond is callable and when. A callable bond should offer a higher yield than a non-callable bond to compensate for this risk.

How to research a municipal bond before buying

The municipality publishes an official statement for each bond issue. This document contains the municipality's financial statements, details about the project being financed, the bond's terms, and the risks involved. You can request this from your broker or find it on the Municipal Securities Rulemaking Board's EMMA database (emma.msrb.org), which is free and open to the public.

Check the municipality's credit rating from at least one of the major rating agencies. Look at the municipality's recent financial reports to see whether revenues are stable or declining. A municipality with shrinking tax revenue is a higher risk than one with stable or growing revenue.

Compare the bond's yield to other bonds with similar maturity and credit rating. If a bond offers significantly higher yield, ask why — it may reflect genuine risk that the market has priced in, or it may be a sign that the bond is undervalued. Your broker should be able to explain the difference.

Frequently Asked Questions

Do I have to hold a municipal bond until it matures?

No. You can sell a municipal bond on the secondary market before maturity. The price you receive depends on current interest rates and the bond's credit rating. If rates have risen since you bought, you may have to sell at a discount. If rates have fallen, you may be able to sell at a premium.

What is the minimum investment for a municipal bond?

Most municipal bonds are issued in denominations of $5,000, though some are $1,000. You buy them through a broker, who may charge a commission or markup. Some brokers offer no-commission trading on certain bonds, but the price may already include a markup.

Can I lose money on a municipal bond?

Yes, in two ways. First, if you sell before maturity when interest rates have risen, you will receive less than you paid. Second, if the municipality defaults, you may not receive all of your principal or interest payments. Holding until maturity protects you from interest rate risk but not from default risk.

Are municipal bonds safer than stocks?

Municipal bonds are generally less volatile than stocks, but they carry different risks. A bond's value depends on interest rates and the issuer's creditworthiness. A stock's value depends on the company's earnings and market sentiment. A high-quality municipal bond from a stable municipality is typically safer than a stock, but a low-rated bond from a struggling municipality may be riskier.

What happens to my municipal bond if the municipality goes bankrupt?

Bondholders are creditors and have a claim on the municipality's assets. In a bankruptcy, secured creditors are paid first, then bondholders, then other unsecured creditors. You may recover some or all of your principal, but the process is slow and the outcome is uncertain. This is why credit rating and financial health matter before you buy.