The tax-equivalent yield is the yield a taxable bond must offer so that its after‑tax return equals the yield on a comparable tax-exempt investment (most commonly a municipal bond). Investors use TEY to make apples-to-apples comparisons between tax-free and taxable fixed-income alternatives.
Key takeaway
– TEY answers the question: “If I’m in my current tax situation, how high would a taxable yield need to be to match the tax-free yield I can get from a municipal bond?”
Formula and how to use it
– TEY = Tax-free yield / (1 − t)
• where t = your marginal tax rate (expressed as a decimal)
– Reverse (to get the tax-free equivalent of a taxable yield):
• Tax-free equivalent yield = Taxable yield × (1 − t)
Practical steps to calculate TEY (step‑by‑step)
1. Identify the tax-free yield
• Example: a municipal bond yields 4.50% (tax‑exempt federal income tax).
2. Determine your marginal tax rate
• Use your federal marginal tax bracket and add any state tax on interest if applicable (see note below about state taxes and other adjustments).
• Example: federal bracket = 24%; no state tax = t = 0.24.
3. Plug into the formula
• TEY = 0.045 / (1 − 0.24) = 0.045 / 0.76 = 0.0592 → 5.92%
4. Compare TEY to taxable alternatives
• A taxable bond must yield at least 5.92% before tax to give the same after‑tax income as the 4.50% muni for someone in the 24% marginal bracket.
Tip: When to include state taxes
– If your state taxes the interest on a particular municipal bond (or all muni interest), include that state marginal rate as well. A practical (simple) approach is to add the state rate to the federal marginal rate to estimate a combined marginal tax rate, but note that interactions (SALT limits, deductions, and AMT) can change effective rates—see caveats below.
Examples (illustrative)
– Example A: 8.00% tax-exempt muni, investor in 22% federal bracket, no state tax:
• TEY = 0.08 / (1 − 0.22) = 0.08 / 0.78 = 0.1026 → 10.26%
– Example B: same 8.00% muni, investor in 37% bracket:
• TEY = 0.08 / (1 − 0.37) = 0.08 / 0.63 = 0.1270 → 12.70%
– Example C (from source details): 7.00% tax-free bond vs. a taxable bond yielding 9.75%
• For low‑ and mid‑brackets (10–24%) 9.75% after tax may still be higher than the 7% muni; for higher brackets the muni becomes comparatively more attractive.
Tax bracket implications — why investor choices vary
– Higher marginal tax rates increase the TEY, making tax‑exempt yields relatively more valuable.
– Investors in low marginal tax brackets often prefer taxable bonds if pre‑tax yields are significantly higher than muni yields; high‑bracket taxpayers frequently find munis more attractive.
When are municipal bonds exempt from federal taxation?
– Municipal bond interest has been largely exempt from regular federal income tax since the federal income tax system’s creation in 1913. The policy rationale is historical and functional: states and local governments finance public infrastructure and services whose costs are partly borne by the federal tax policy (and, historically, questions about constitutional taxing powers influenced the rule). In short, muni interest is generally federally tax‑exempt because Congress designed tax policy to support state/local financing of public goods (Congressional Research Service; historical summaries). [See CRS background on tax-exempt bonds.]
Are municipal bonds subject to state tax?
– It depends:
• Many states exempt interest on municipal bonds issued by that state or its localities for residents of that state (in‑state munis).
• Interest from out‑of‑state municipal bonds may be taxable by your state.
• Some states fully exempt muni interest; some tax certain munis; rules vary by state.
– Action: always check your state tax rules (or consult your tax advisor) before assuming state tax treatment.
When are capital gains taxes applied to tax-free investments?
– Capital gains taxes apply when you sell an investment (including tax-exempt bonds) for more than your cost basis. Specific items to watch:
• Selling a municipal bond at a gain → subject to capital gains tax.
• Mutual funds or ETFs made up of tax‑exempt bonds can distribute capital gains to shareholders; those are taxable.
• Purchase at a market discount: the IRS may tax certain discounts as ordinary income upon sale or disposition (market discount rules).
• Original Issue Discount (OID) and premium/amortization rules: special IRS rules can affect how bond purchase price vs. par value is treated over time.
– See IRS guidance on capital gains and bond discount/ OID rules (IRS Topic No. 409 and related publications).
Other important tax considerations and limitations
– Alternative Minimum Tax (AMT): Interest on certain private‑activity municipal bonds may be includable in AMT calculations; that can make otherwise tax‑free interest effectively taxable under AMT. Check the bond’s tax status.
– Net Investment Income Tax (NIIT): high‑income taxpayers may be subject to an additional 3.8% NIIT on investment income.
– State and local tax interplay: the SALT (state and local tax) deduction cap and other personal deductions can change effective tax rates. Don’t rely solely on statutory bracket; determine your actual marginal tax bite with state rules and deductions considered.
– Credit risk, call risk, liquidity and duration: TEY compares only tax effects and yield levels. Investment choice must also consider credit quality, call provisions, duration and interest rate risk, and portfolio diversification.
– Municipal bond funds vs. individual bonds: funds provide diversification but may distribute taxable capital gains; individual bonds held to maturity avoid capital gain/loss (assuming no default) but have credit and liquidity considerations.
Practical checklist before choosing
1. Determine your true marginal tax rate (federal + state, consider NIIT and AMT).
2. Get the pre‑tax yield on the taxable alternative and the tax‑free coupon/yield.
3. Compute TEY for the tax‑free option: tax-free yield / (1 − combined marginal tax rate).
4. Compare TEY to the taxable bond yield. If taxable yield > TEY, the taxable bond should produce a higher after-tax return.
5. Confirm bond specifics: issuer, call features, state tax treatment, AMT status, credit rating.
6. For funds: review historical capital gain distributions and turnover.
7. Consult a tax advisor for complex situations or significant capital sums.
Quick example of combined state + federal rate (practical approximation)
– If federal = 24% and your state taxes interest at 5%, a simple approximation is to add the two: combined marginal ≈ 0.24 + 0.05 = 0.29 (29%). TEY = tax-free yield / (1 − 0.29). Note: this is a practical heuristic; interactions, deductions and AMT effects can change your effective rate—get professional tax help for precision.
The bottom line
– TEY is a simple, helpful tool to compare tax-exempt municipal yields with taxable alternatives. It converts tax-exempt yields into the taxable yield equivalent given your tax situation so you can make clearer investment decisions.
– Remember to factor in state tax treatment, AMT exposure, possible capital gains from funds or sales, and non‑tax considerations such as credit risk and interest‑rate risk. The “best” choice depends on your full financial picture and tax circumstances; consult a tax or financial advisor for personalized guidance.
Sources and further reading
– Investopedia — “Tax-Equivalent Yield” (source article summary):
– Congressional Research Service — “Tax-Exempt Bonds: A Description of State and Local Government Debt” (background on muni exemption)
– Internal Revenue Service — Topic No. 409: Capital Gains and Losses (rules on taxability of gains) and IRS guidance on bond discount/OID and inflation adjustments
Editor’s note: The following topics are reserved for upcoming updates and will be expanded with detailed examples and datasets.