Treasury Bonds: Federal-Taxable, State-Exempt
U.S. Treasury bonds (T-bonds, T-notes, T-bills) generate interest income that's taxable at the federal level but EXEMPT from state and local income taxes. This is a unique benefit only Treasuries get.
For a high-bracket investor in a high-tax state (California 13.3%, NYC ~13%), the state tax exemption is significant. A 5% Treasury yield = 5% federal-taxable but 0% state. A 5% corporate bond at the same nominal yield = 5% federal-taxable PLUS state tax. The Treasury's after-state-tax yield is higher.
Calculation example: California resident in 24% federal + 9.3% state bracket. 5% Treasury after-tax yield: 5% × (1 - 0.24) = 3.80% (no state tax). 5% corporate after-tax yield: 5% × (1 - 0.24 - 0.093) = 3.34%. Treasury wins by 0.46 percentage points.
Treasury types: T-bills (mature in 1 year or less), T-notes (2-10 years), T-bonds (20-30 years), TIPS (Treasury Inflation-Protected Securities), I bonds. All share the state tax exemption.
Held in tax-advantaged accounts (IRA, 401(k)): the state tax exemption is wasted. You're not paying state tax on retirement account interest anyway. Hold corporate bonds or other taxable bonds in IRAs, save Treasuries for taxable accounts where the exemption matters.
Municipal Bonds: Federal-Exempt (Mostly)
Municipal bonds (issued by states, cities, counties) generate interest that's federal-tax-exempt. For high-bracket investors, this is the main appeal of munis.
Most state munis are also exempt from that state's income tax (residents). California muni interest is California-tax-free for California residents, federal-tax-free for everyone. Out-of-state munis are federal-tax-free but typically subject to your state's income tax.
Calculation example: high-bracket investor in California (37% federal + 13.3% state). 4% California muni yield: 4% × (1 - 0 - 0) = 4.00% after-tax. Equivalent taxable corporate bond yield needed to match: 4% / (1 - 0.50) = 8% pre-tax yield. So the 4% muni is equivalent to an 8% corporate bond.
Tax-equivalent yield (TEY) calculation: TEY = muni yield / (1 - marginal tax rate). For a 35% combined federal+state bracket, TEY of a 4% muni is 4% / 0.65 = 6.15%. Compare your muni yields to corporate yields on this TEY basis to determine which is better.
Private Activity Bonds (PABs): a subset of munis (issued for non-government purposes — airports, hospitals, university construction) that are federal-tax-exempt for regular tax but TAXABLE for AMT. Avoid PABs if AMT-exposed.
AMT-free muni funds explicitly exclude PABs. Vanguard's Tax-Exempt Bond Index Fund (VTEB) excludes PABs. Useful for AMT-exposed investors.
Corporate Bonds: Fully Taxable
Corporate bonds (issued by companies) generate interest taxable at federal AND state levels. No exemptions.
Higher yield to compensate for taxability: corporate bonds typically yield more than equivalent-quality Treasuries because of the tax disadvantage. The yield difference compensates somewhat for the additional tax burden.
After-tax yield comparison matters: a 5.5% corporate bond may seem better than a 4.5% Treasury. But for a California resident in 24% federal + 9.3% state bracket: corporate after-tax = 5.5% × (1 - 0.333) = 3.67%. Treasury after-tax = 4.5% × (1 - 0.24) = 3.42%. Corporate still wins, but only by 0.25%, not the apparent 1%.
Corporate bonds in taxable accounts: typically a poor choice for high-bracket investors. The full taxation of interest erodes returns. Consider muni bonds (federal-exempt) or Treasuries (state-exempt) instead.
Corporate bonds in IRAs: appropriate. The IRA shelters the interest from current taxation. The yield advantage over munis (which are federal-tax-free regardless) makes corporates more efficient in the IRA.
Credit risk: corporate bonds have credit risk (issuer might default). Treasury and muni bonds have varying credit risk. The yield premium for corporates partially compensates for credit risk plus tax disadvantage.
TIPS: The Phantom Income Trap
Treasury Inflation-Protected Securities (TIPS) adjust principal value for inflation. When inflation rises, the principal increases. When the bond eventually matures, you receive the inflation-adjusted principal.
Tax issue: the inflation adjustment to principal is taxable as ordinary income IN THE YEAR THE ADJUSTMENT OCCURS — even though you don't receive the cash until maturity (or sale). This creates 'phantom income' — taxable income with no corresponding cash.
Concrete example: $10K TIPS purchase at par. Year 1: inflation 4%. Principal increases to $10,400. The $400 of inflation adjustment is taxable income for the year (federal — Treasury still state-exempt). You don't receive the $400 in cash but you owe federal tax on it. Plus your normal coupon interest.
Because of phantom income, TIPS held in taxable accounts can produce negative after-tax cash flow during high-inflation periods. The taxes owed on inflation adjustments may exceed coupon income.
Solution: hold TIPS in tax-advantaged accounts (IRA, 401(k)). The phantom income doesn't matter when the account is tax-deferred. TIPS provide their full inflation-protection benefit without the tax timing problem.
Series I bonds (I-bonds) avoid this issue: they accrue inflation adjustments tax-deferred until redemption. You can hold I-bonds in taxable accounts without phantom income concerns. But annual purchase limit is $10K per person.
Series I Bonds: The Tax-Deferred Inflation Hedge
Series I bonds combine a fixed rate plus an inflation rate (resets every 6 months based on CPI). Interest accrues but is tax-deferred until redemption. Federal-taxable when redeemed; state-tax-exempt always.
Annual purchase limit: $10,000 per person ($20K married couple) of electronic I-bonds, plus up to $5,000 of paper I-bonds purchased with tax refund. Limits make I-bonds a small allocation for most investors.
5-year holding penalty: redeem within 5 years and forfeit the most recent 3 months of interest. Hold for 5+ years to capture all interest. Maximum hold: 30 years (after which they stop earning interest and you should redeem).
Education exclusion: I-bond interest can be entirely tax-free if used for qualified education expenses (subject to income phase-outs). Useful for parents saving for kids' college.
I-bonds during high-inflation periods (2022-2023) had yields of 9%+. Even now in 2026 (lower inflation), they remain reasonable. The combination of inflation protection, tax deferral, state-tax exemption, and federal-tax-deferred interest makes I-bonds the most tax-efficient cash-equivalent for many investors.
Asset Location Strategy
Bonds in taxable accounts: prefer Treasuries (state-exempt) for high-state-tax investors, munis (federal-exempt) for high-federal-bracket investors, I-bonds (deferred + state-exempt) for tax-efficient cash positions.
Bonds in Traditional IRA / 401(k): hold corporate bonds, REITs, high-turnover funds — anything that generates ordinary income annually. The IRA shelters the income, and taxes are eventually paid as ordinary income at withdrawal regardless of the underlying source. So corporates' yield advantage compounds tax-deferred.
Bonds in Roth IRA / Roth 401(k): tax-free growth means hold investments expected to have highest returns and highest tax-drag. Bonds are typically a poor fit — their lower expected returns mean Roth space is 'wasted' on them. Reserve Roth for aggressive growth assets.
TIPS specifically: hold in Traditional IRA / 401(k) to avoid phantom income tax timing issues.
International bonds: typically subject to foreign withholding tax that can be claimed as foreign tax credit only in taxable accounts. Hold in taxable to capture FTC.
The general principle: tax-inefficient assets (high turnover, ordinary income generators) belong in tax-deferred accounts. Tax-efficient assets (low turnover, qualified dividends, muni interest) belong in taxable accounts. Highest-growth assets belong in Roth.
After-tax yield calculations across account types: a 5% corporate bond in a taxable account at 35% combined rate = 3.25% after-tax yield. The same bond in Traditional IRA grows at 5% but eventually withdrawal taxed at 22% = effective 3.9% after-tax yield. The same bond in Roth IRA = 5% pure (no tax). Asset location captures these differences.