Municipal Bonds
Debt issued by states, cities and their agencies. The interest is generally exempt from federal tax, which changes how the yield should be compared to anything else.
MadStockAlerts Research · Updated August 29, 2026
What to take away
- Interest is generally exempt from federal income tax and often from state tax in the issuing state.
- Comparing a municipal yield to a taxable one requires a taxable-equivalent calculation.
- General obligation and revenue bonds are backed by different things.
- The market is fragmented, with a very large number of small issuers.
- Some municipal bonds are taxable, and some are subject to the alternative minimum tax.
MAD Academy Training Video · 0:46
Compare After Tax, Not Before
A municipal bond's lower yield can be worth more than a corporate's higher one, and only the taxable-equivalent yield reveals it.
This lesson is part of a Stock Alerts + Tools plan.
The tax feature and the comparison it requires
Because the interest is generally exempt from federal tax, a municipal yield cannot be compared directly to a corporate or Treasury yield. The comparison requires converting it to a taxable-equivalent figure.
taxable-equivalent yield = municipal yield / (1 - marginal tax rate)
- the marginal rate is the rate that would apply to the additional income
- a 3.5 percent municipal yield at a 32 percent marginal rate is equivalent to about 5.15 percent taxable
The consequence is that the same bond is a different proposition for different holders. The benefit rises with the marginal rate, which is why these bonds are held disproportionately by higher-rate taxpayers and why they are generally unsuited to tax-advantaged accounts.
This describes how the arithmetic works and is not tax advice. State treatment, the alternative minimum tax and individual circumstances all affect the outcome.
Scroll the chart sideways to see all of it.
The two main types
| General obligation | Revenue | |
|---|---|---|
| Backed by | The issuer's taxing power and full faith and credit | Revenue from a specific project or system |
| Examples | A state or a city's general debt | A toll road, a water utility, an airport |
| Main risk | The issuer's fiscal position | Whether the project generates the projected revenue |
| Recovery in distress | Depends on the legal framework and the issuer | Limited to the pledged revenue |
The second column is the larger share of the market and carries project-specific risk that a general obligation does not. A revenue bond for a facility whose usage falls short of projections is exposed to that shortfall directly.
The structure of the market
- There are tens of thousands of issuers, from states to small districts, each with its own credit.
- Individual issues are frequently small, and many trade rarely or never after issuance.
- Retail holders own a large share of the market directly, which is unusual among bond markets.
- Disclosure is governed by a different regime from corporate issuers, with continuing disclosure through a central repository.
The fragmentation has a practical consequence: spreads on small issues can be wide, and price discovery is limited. A bond that has not traded in months has a marked price rather than an observed one.
The exceptions to the exemption
| Category | Treatment |
|---|---|
| Ordinary municipal bonds | Federally tax-exempt interest |
| Private activity bonds | Interest may be subject to the alternative minimum tax |
| Taxable municipals | Issued for purposes that do not qualify; interest is taxable |
| Capital gains on any municipal | Taxable, since the exemption covers interest and not gains |
The last row surprises holders regularly. Selling a municipal bond above its cost produces a taxable capital gain in the ordinary way, and only the coupon interest is exempt.
A bond bought at a discount can also produce ordinary income under specific rules on market discount, which is exactly the kind of detail that requires a professional rather than a general description.
Credit in the municipal market
Default rates on municipal bonds have historically been far lower than on comparably rated corporate bonds, which is one of the market's defining characteristics and is frequently overstated into an assumption of safety.
- General obligation defaults have been rare, and they have occurred.
- Revenue bonds for specific projects have defaulted at materially higher rates than general obligations.
- Certain sectors, including some healthcare, housing and industrial development issues, carry substantially more risk than the market's average implies.
- The legal framework for a default varies by state, and some states restrict municipal bankruptcy entirely.
The last item is a structural point that has no corporate equivalent. What happens to a defaulted municipal issuer depends on state law as much as on the bond's terms, and the outcomes have varied widely across the cases that exist.
Continuing disclosure is filed to a central repository, and the quality of it varies. An issuer that has not filed current financial information is a specific and checkable condition rather than an impression.