What Is Tax-Equivalent Yield? Explained Simply

Two bond quotes sit on the same screen. One corporate bond yields 5.1%. One municipal bond yields 3.6%. Your first instinct is to take the higher number. That instinct is incomplete. If the muni interest is exempt from federal income tax, the lower coupon can still leave more cash in your pocket after April. The tool that makes that comparison fair is tax-equivalent yield, often shortened to TEY.

This guide explains what tax-equivalent yield means, the exact formula, worked examples with 2026-style federal brackets labeled as educational illustrations, when munis beat taxable bonds or brokered CDs, how state tax changes the math, a light note on the alternative minimum tax, and the pitfalls that trip careful savers. It is warm education for U.S. readers using American dollars. It is not personalized tax, legal, or investment advice.

What Tax-Equivalent Yield Actually Means

Tax-equivalent yield translates a tax-free interest rate into the taxable interest rate that would produce the same after-tax income. You ask: "What would a taxable bond or CD need to pay me so that, after I pay tax on that interest, I end up even with this tax-free muni?"

Investor.gov and SEC investor materials note that municipal bond interest is generally exempt from federal income tax, and may also be exempt from state and local tax if you live in the issuing state. Because of that benefit, tax-exempt muni yields are usually lower than yields on comparable taxable bonds. TEY puts both sides on one ruler so you are not comparing a pre-tax apple to an after-tax orange.

Three reminders keep the idea honest:

• TEY is about interest income. It does not automatically make price gains tax-free.
• TEY assumes the interest is truly tax-exempt for you. Some private-activity bonds and some situations are different.
• TEY ignores differences in credit, call risk, liquidity, and fees unless you adjust those separately.

The Formula (And Why It Works)

The standard federal-only formula is:

Tax-equivalent yield = tax-free yield / (1 - marginal tax rate)

If the tax-free yield is 3.5% (0.035) and your marginal federal rate is 24% (0.24), then:

TEY = 0.035 / (1 - 0.24) = 0.035 / 0.76 = 0.04605, or about 4.61%.

Why divide? Imagine a taxable investment that pays rate R. After federal tax at rate t, you keep R times (1 - t). You want that after-tax amount to equal the tax-free yield Y. So R times (1 - t) equals Y, which means R equals Y / (1 - t). That R is the tax-equivalent yield.

Use your marginal rate on ordinary investment interest, not your average tax rate. Marginal means the rate on the next dollar of taxable interest. Average rate mixes lower brackets and credits and will usually understate the value of the exemption.

2026 Federal Brackets: Use Carefully Labeled Examples

The IRS publishes federal income tax rates and brackets and updates them for inflation. For tax year 2026, publicly reported ordinary rates still run through familiar steps such as 10%, 12%, 22%, 24%, 32%, 35%, and 37%, with dollar thresholds that differ by filing status. Bracket edges move with inflation adjustments, and your exact edge depends on taxable income and filing status. When you are not staring at your own return, it is safer to say "about" or to label figures as examples.

In the worked examples below, we treat 22%, 24%, 32%, and 37% as illustrative marginal rates a reader might face on taxable bond interest. Confirm your own bracket on current IRS tables before making a real comparison.

Worked Examples: Same Muni, Different Brackets

Hold the tax-free yield fixed at 3.50% and change only the federal marginal rate.

Same bond. Same coupon. Very different "what taxable yield do I need?" answers. That is why a retiree in a lower bracket and a dual-income household in a higher bracket can look at identical muni quotes and reach opposite conclusions, both of them mathematically consistent.

Dollar check on $10,000 face value for one year of simple interest (illustrative, ignoring compounding within the year and price changes):

• Tax-free muni at 3.50%: $350 of interest, generally not federally taxed as ordinary interest if it qualifies.
• Taxable bond at 4.61% in a 24% bracket: $461 of interest, federal tax about $461 times 0.24 = $110.64, leaving about $350.36 after federal tax.
• Taxable bond at 5.15% in a 32% bracket: $515 of interest, federal tax about $515 times 0.32 = $164.80, leaving about $350.20 after federal tax.

The TEY formula is doing the same job as that after-tax arithmetic, just faster.

When Munis Beat Taxable Bonds

A muni "beats" a taxable bond on income when the muni's tax-equivalent yield is higher than the taxable bond's yield (or when the taxable bond's after-tax yield is lower than the muni yield). Flip the formula if you prefer the other direction:

After-tax taxable yield = taxable yield times (1 - marginal tax rate)

Example A. Corporate bond yields 5.00%. Muni yields 3.50%. Your federal marginal rate is 32%.

• Corporate after-tax: 5.00% times 0.68 = 3.40%.
• Muni: 3.50% tax-free.
• Muni TEY: 3.50% / 0.68 = about 5.15%.

On pure federal income math, the muni wins (3.50% after tax versus 3.40%, or TEY 5.15% versus a 5.00% taxable quote).

Example B. Same yields, but your federal marginal rate is only 22%.

• Corporate after-tax: 5.00% times 0.78 = 3.90%.
• Muni: 3.50%.
• Muni TEY: 3.50% / 0.78 = about 4.49%.

Now the taxable corporate bond wins on income alone. The "better" bond flipped without either yield changing. Your bracket did the flipping.

Break-even taxable yield is exactly the TEY. If a taxable quote is above that line, it wins on federal income. If it is below, the muni wins. Draw that line before you fall in love with a coupon.

Federal Tax Versus State Tax

Federal exemption is the headline feature. State tax is the fine print that can still move hundreds of dollars a year on a sizable bond ladder.

Common patterns:

• In-state munis: Interest is often exempt from both federal and that state's income tax for residents, which raises the effective TEY.
• Out-of-state munis: Interest may still be federally tax-exempt but taxable at the state level, which lowers the advantage versus an in-state bond.
• U.S. territory bonds: Investor materials often note that interest from certain territory issuers can be treated favorably for state tax in many places. Verify current rules for your state.
• Treasuries: Interest on U.S. Treasury bills, notes, and bonds is federally taxable but generally exempt from state and local income tax. That is a different tax puzzle than munis, and TEY logic still helps when you compare a Treasury to a fully taxable corporate bond in a high-tax state.

A simple combined-rate illustration (educational only): suppose your federal marginal rate is 32% and your state marginal rate on interest is 5%, and the muni is exempt from both. One common combined estimate when state tax is deductible federally is:

Combined rate = 0.32 + 0.05 times (1 - 0.32) = 0.32 + 0.034 = 0.354, or 35.4%.

Then TEY = 3.50% / (1 - 0.354) = 3.50% / 0.646 = about 5.42%.

Compare that with the federal-only TEY of about 5.15%. The state exemption added roughly 0.27 percentage points to the equivalent taxable yield in this labeled example. SALT deduction limits and state conformity rules can change the combined-rate shortcut, so treat it as a planning sketch, not a filed return.

Corporate Bonds Versus Munis

Corporate bonds usually offer higher pre-tax yields than high-quality munis of similar maturity because buyers demand compensation for credit risk and for the fact that the interest is taxable. That does not mean corporates always win after tax.

Compare along these axes, not just the coupon:

• Credit: A single-A corporate and a single-A muni are closer cousins than a junk corporate and a top-rated general obligation muni.
• Sector and revenue source: General obligation munis lean on taxing power. Revenue munis lean on project cash flows such as tolls or utilities. Corporates lean on company cash flow and capital structure.
• Call features: Many munis are callable. A rich coupon that disappears in a refinancing is not the same as a locked long TEY.
• Liquidity and spreads: Individual munis can be awkward to sell in small lots. Corporate bond ETFs and large corporates may be easier to exit, with their own trade-offs.
• Account type: In a taxable brokerage account, the muni exemption can matter a lot. Inside a traditional IRA, the federal exemption is often redundant.

Side-by-side labeled example on $25,000 for one year of simple interest:

• Corporate at 5.20%, 32% federal bracket: interest $1,300; federal tax about $416; after-tax about $884 (3.54% after tax).
• Muni at 3.60%, same bracket, federally tax-exempt interest: $900 kept (3.60%).
• Muni TEY: 3.60% / 0.68 = about 5.29%.

Here the muni still wins on federal income ($900 versus $884) even though its coupon looks weaker. If the corporate were higher quality, shorter duration, or easier to sell, you might still prefer it for non-yield reasons. TEY settles the tax math. It does not settle the whole portfolio decision.

Brokered CDs Versus Munis

Brokered certificates of deposit are bank deposits you buy through a brokerage. Interest is generally taxable at the federal level (and often at the state level). Many CDs carry FDIC insurance up to applicable limits when structured correctly, which is a different safety story than municipal credit.

Use TEY the same way. Example:

• Brokered CD yield: 4.20% taxable.
• Muni yield: 3.20% tax-free federally.
• Your federal marginal rate: 24%.

Muni TEY = 3.20% / 0.76 = about 4.21%. On federal income alone, the two are nearly tied. Nudge the CD to 4.40% and the CD wins on income. Nudge your bracket to 32% and the same 3.20% muni has a TEY of about 4.71%, which beats the 4.20% CD.

Other CD versus muni differences matter as much as TEY:

• Early exit: Bank CDs often have early withdrawal penalties. Brokered CDs may need to be sold on the secondary market at a price that can be above or below face value.
• Insurance versus credit: FDIC coverage (within limits) is not the same as a muni rating. Do not treat them as identical "safe yield" products.
• State tax: A Treasury bill can be state-tax friendly. A CD usually is not. An in-state muni might be exempt at both levels.
• Cash needs: Money you may need within months often belongs in instruments that match that horizon, whether that is a short CD, a Treasury bill ladder, or a high-yield savings account, not a long muni bought only because the TEY looked pretty.

A Light Note on AMT

Most everyday readers will use the ordinary TEY formula and stop there. One exception deserves a short flag. Interest on certain private-activity municipal bonds can be a preference item for the alternative minimum tax (AMT). IRS materials on tax-exempt interest and Publication 550 discuss private-activity bonds and related reporting. Fund 1099 forms often show exempt-interest dividends and any portion that may be an AMT preference.

If you are near AMT territory, a "tax-free" private-activity yield may not be fully free in practice. Prefer bonds and funds labeled with your AMT situation in mind, or run the numbers with a tax professional before overweighting a fat AMT-subject yield.

How to Run the Comparison in Five Steps

1. Confirm the interest is tax-exempt for you. Read the official statement, fund fact sheet, or 1099 language. Do not assume every "muni" coupon is federally exempt in your hands.
2. Pick the right marginal rate. Use the ordinary rate that would hit the taxable interest you are comparing against. Add state tax thoughtfully when the exemption applies.
3. Compute TEY. Divide the tax-free yield by (1 - rate). Or compute after-tax taxable yield and compare directly to the muni yield.
4. Match the risk package. Align maturity or duration, credit quality, call features, and liquidity as closely as you can.
5. Place the holding in the right account. Taxable account versus IRA can reverse which product is efficient even when TEY looks great.

Pitfalls That Break the Math

Using average tax rate instead of marginal rate. Average rates blend lower brackets. TEY needs the rate on the next dollar of interest.

Comparing a long callable muni to a short CD. Different interest-rate risk and reinvestment risk. Equalize the timeline first.

Ignoring premium bonds and yield-to-worst. A high coupon bought above par can be called away. Yield-to-worst is often the honest comparison number, then convert that with TEY.

Forgetting that capital gains are different. Selling a muni at a profit is generally not the same as collecting tax-exempt interest. Basis, premium amortization, and market discount rules can appear on real returns.

Stuffing munis into tax-deferred accounts by habit. You may give up the exemption's value and still pay ordinary tax on withdrawals later.

Chasing the highest TEY without credit homework. A distressed issuer's fat yield can look wonderful in a spreadsheet and painful in a default. SEC investor bulletins on municipal credit risk exist for a reason.

Skipping fees on funds. A muni bond fund's expense ratio comes out of your return. Compare net yields, then apply TEY thinking to the tax-exempt share of income.

Inflation, Reinvestment, and Why TEY Is Not a Total-Return Crystal Ball

Tax-equivalent yield answers an income-tax comparison. It does not tell you whether real purchasing power holds up if inflation runs hot, whether you can reinvest coupons at similar rates, or how the bond's price will mark to market if you sell early. Treasury and Federal Reserve interest-rate releases are useful context for the rate environment. Consumer price data from the Bureau of Labor Statistics is useful context for inflation. Neither replaces the TEY calculation, and TEY does not replace them.

If you reinvest after-tax cash flows for many years, small TEY edges compound. The slider below is a general compounding sandbox so you can feel how rate and time interact. It is not a muni predictor. Plug in an after-tax rate you believe is realistic for your comparison.

Putting It Together With Honest Numbers

Walk one full comparison as a checklist you can reuse.

Setup: You are comparing a 10-year-ish investment-grade corporate yielding 4.90% with a high-quality in-state muni yielding 3.40%. Your illustrative federal marginal rate is 24%. Your state marginal rate on taxable interest is about 5%, and the in-state muni is exempt from both.

Federal-only TEY: 3.40% / 0.76 = about 4.47%. The corporate at 4.90% still wins on federal income alone.

Combined sketch: Combined rate = 0.24 + 0.05 times (1 - 0.24) = 0.24 + 0.038 = 0.278. TEY = 3.40% / (1 - 0.278) = 3.40% / 0.722 = about 4.71%. Now the race tightens. The corporate still leads slightly on this sketch (4.90% versus 4.71% TEY), but a half-point move in either yield or a higher federal bracket could flip it.

After-tax corporate with state tax ignored for a moment: 4.90% times 0.76 = 3.724% after federal tax, versus 3.40% muni. Corporate still ahead federally. Add state tax on the corporate interest and the gap shrinks further. Exact state withholding and deduction limits belong on a real worksheet, not in a blog slogan.

That is the point of TEY done well. You do not memorize a winner. You build a fair after-tax line, then decide whether credit, liquidity, calls, and account location still favor one side.

Who Benefits Most From Thinking in TEY

Households in higher ordinary brackets who hold bonds in taxable accounts often gain the most from a disciplined TEY habit, especially in states with meaningful income tax and a deep local muni market. Households in lower brackets, or those who already keep fixed income inside IRAs and 401(k)s, may find taxable bonds, Treasuries, or CDs win more often even when muni ads look appealing.

New investors sometimes treat TEY as a reason to buy only munis. That overcorrects. Equity risk, emergency reserves, debt payoff, and retirement account contributions still dominate most wealth plans. TEY is a specialized ruler for comparing taxable and tax-exempt fixed income. Use it there. Do not let it become the whole map.

A Calm Bottom Line

Tax-equivalent yield is a translation device. It says: take the tax-free yield, divide by (1 minus your marginal tax rate), and you will see the taxable yield that matches it after tax. Work the arithmetic with your real bracket. Adjust for state tax when the exemption applies. Match credit and maturity before you declare a winner. Watch AMT on private-activity bonds. Remember that gains, calls, fees, and account location can override a pretty TEY.

When you can do that without squinting, the 3.6% muni and the 5.1% corporate stop being a beauty contest of bigger numbers. They become a clear after-tax choice you can explain in one sentence. That is the whole job of tax-equivalent yield, explained simply, for 2026 readers who want the math without the mystique.