Municipal Tax Exemption & TFEY

It’s important to understand how income from debt securities is taxed. The tax treatment depends on who issues the bond.

🔑 Master tax table — federal vs. state vs. local by issuer

Corporate bonds

Interest paid by corporate bonds is fully taxable as ordinary income. That means it can be subject to:

• Federal income tax
• State income tax (if the state has one)
• Local income tax (if the city/locality has one)

Federal tax on ordinary income depends on the investor’s marginal tax bracket (up to 37%). Some states and cities impose their own income taxes, while others do not.

US Government bonds

Interest paid by US Government bonds is:

• Subject to federal income tax
• Exempt from state and local income taxes

Because federal tax is usually the largest portion of an investor’s income tax bill, the state/local exemption often produces only modest savings. The size of the savings depends on the investor’s state.

Municipal bonds

Interest paid by municipal bonds is:

• Exempt from federal income tax
• Potentially subject to state and local income taxes

In practice, many investors pay no tax on municipal bond interest. If you buy a municipal bond issued by your state of residence, the interest is typically exempt from federal tax, state tax, and local tax.

Bottom line: state residents do not pay interest taxes on municipal bonds from their state.

🔑 US territories (their bonds are municipal bonds, always tax-free regardless of residence)

Example: residents of Alaska who purchase US Virgin Islands bonds receive all interest fully tax-free.

Sidenote: Alternative minimum tax (AMT)

In most cases, you can assume municipal bond interest is tax-free when purchased by a resident. The most common reason municipal bond interest becomes taxable is the alternative minimum tax (AMT).

• The purpose of AMT is to ensure taxpayers are “paying their fair share.”
• When AMT applies, certain items that are normally tax-deductible or tax-exempt can become taxable, increasing overall tax liability.
• AMT is generally a concern for wealthier investors in higher tax brackets.

🔑 Typical private activity bond structure

1. A municipality issues the bond to raise capital for a private project.
2. The private entity (not the municipality) is responsible for generating the cash flow used to repay investors.
3. Investors may receive tax-exempt interest, which usually allows the bond to be issued at a lower interest rate.

Example: a private developer could work with your city to build a new airport. The city issues a private activity bond to raise capital for the developer. The developer uses the proceeds to build the airport and repays investors using revenues generated by the airport.

Who should buy municipal bonds

Municipal bonds tend to fit a specific investor profile. Like other bonds, they can provide income, but their tax benefits affect their yields.

• Because municipal bond interest is often tax-exempt, municipal bonds usually offer lower interest rates and yields than comparable taxable bonds.
• The tax benefit needs to be large enough to make up for the lower yield.
• In general, an investor must be in a high tax bracket to justify choosing a lower-yielding municipal bond.
• With a progressive tax system, higher tax brackets apply as reportable income increases. If the investor’s tax bracket is low, the tax benefit may not be worth giving up yield.

🔑 Tax-free equivalent yield (TFEY) formula

TFEY = CY x (100% - TB)

Your guide: TFEY = tax-free equivalent yield CY = corporate yield TB = tax bracket

Worked example 1 — 37% tax bracket

A wealthy investor in the 37% tax bracket is considering a corporate bond yielding 7% or a municipal bond yielding 5%.

TFEY = CY x (100% - TB) TFEY = 7% x (100% - 37%) TFEY = 7% x 63% TFEY = 4.4%

At first glance, the corporate bond’s 7% yield looks better. But corporate bond interest is fully taxable, while the municipal bond interest is tax-free (assuming the investor is a resident).

After taxes, the corporate bond yields 4.4%, which is below the municipal bond’s 5% tax-free yield. In this situation, the municipal bond is the better choice because the investor’s tax bracket is high.

Worked example 2 — 25% tax bracket

An investor at the 25% tax bracket is considering a corporate bond yielding 7% or a municipal bond yielding 5%. What is the tax-free equivalent yield of the corporate bond?

TFEY = CY x (100% - TB) TFEY = 7% x (100% - 25%) TFEY = 7% x 75% TFEY = 5.25%

With a 25% tax bracket, the corporate bond’s after-tax yield (5.25%) is higher than the municipal bond’s 5% tax-free yield.

This is why municipal bonds are only suitable for those at high tax brackets.

Municipal bonds and retirement plans

• Retirement plans, like individual retirement accounts (IRAs), are tax-sheltered investment accounts.
• No matter what type of investment is in the account, the investor does not pay taxes at the time they make a return on their investments. Taxes are generally paid when the account owner pulls money out of the account in retirement.
• Investors typically avoid municipal bonds in retirement accounts because the account already provides a tax shelter. It usually doesn’t make sense to buy a low-yielding, tax-free bond inside an account where taxes are already deferred or avoided.
• Instead, investors often hold higher-yielding taxable bonds (like corporate or US Government bonds) in the retirement account and benefit from the account’s tax treatment.

Key points

Corporate bond interest

• Subject to federal, state, and local taxes

US Government bonds interest

• Subject to federal taxes
• Exempt from state and local taxes

Municipal bond interest

• Exempt from federal taxes
• Subject to state and local taxes
• Exempt from all taxes if a resident

Typical municipal bond investor

• Investors seeking income
• Wealthy investors at high tax brackets

Tax-free equivalent yield

• TFEY = Corp. yield x (100% - tax bracket)

Sources

Primary/official references for the material in this chapter. Every link was fetched and returned HTTP 200 on 2026-08-15.