Treasury Interest Escapes Your State, Not the IRS
This is one of the few tax rules in American investing that is genuinely simple at the centre and genuinely fiddly at the edges. Interest paid by the federal government is off-limits to state and local income tax. That is settled law, not a planning trick. What trips people up is what happens when the same Treasuries are held inside a fund, and what the exemption is actually worth once you put a number on it.
- The answer:: Interest on Treasury bills, notes, bonds, savings bonds (including EE and I bonds) and TIPS is exempt from state and local income tax. It remains fully taxable at the federal level.
- The catch:: Hold Treasuries inside a mutual fund or ETF and the exemption passes through only in proportion to the fund's US government obligation percentage — and several states require the fund to clear a threshold before any of it passes through.
- What it is worth:: Your state marginal rate multiplied by the interest. In a state with no income tax the exemption is worth exactly nothing, which makes it a poor reason on its own to prefer Treasuries.
- The mirror image:: Municipal bond interest is generally exempt from federal tax instead, and from your state's tax when the bond is issued in your state. The two exemptions point in opposite directions.
Where the AI summary above gets this wrong
"Treasury bonds are tax-free, so they are a good choice for tax-efficient investing."
That's surface-true. Here's what it misses:
- "Tax-free" is half the sentence — Treasury interest is exempt from state and local income tax only. It is ordinary income federally, taxed at your marginal rate, and for most investors the federal bill is the larger of the two by a wide margin.
- The exemption can be worth nothing — Nine states levy no broad personal income tax. If you live in one, the state exemption on Treasury interest has no value at all, and the comparison against a corporate bond or CD should be made on yield alone.
- Funds are not the same as bonds — A Treasury bond held directly passes its exemption straight through. The same bonds inside a fund pass it through only as a percentage, and in California, New York and Connecticut only if the fund holds enough government obligations to clear a statutory threshold.
01 What the exemption covers, and what it does not
Interest paid on securities issued by the federal government is exempt from state and local income taxation. That covers the whole marketable range — Treasury bills, notes and bonds, and Treasury Inflation-Protected Securities — along with savings bonds, both the EE and I series.
The exemption stops there. The same interest is ordinary income for federal purposes and is taxed at your marginal federal rate in the year you receive it. Your broker reports it on Form 1099-INT, and the state-exempt portion is broken out separately so you can subtract it on your state return. Nothing about the arrangement is a loophole; it is a long-standing rule about which government may tax the other's paper.
It is worth being precise about the direction, because the two big fixed-income exemptions in American investing run opposite ways. Treasury interest escapes the state and pays the IRS. Municipal bond interest generally escapes the IRS and, when the bond was issued in the state where you live, escapes the state as well. Which one suits you is a question about your two marginal rates, not about which is described as tax-free.
Source: Topic no. 403, Interest received
02 Inside a fund, the exemption becomes a percentage
Most people do not hold individual Treasuries. They hold a Treasury money market fund, a short-term government bond fund or a broad bond ETF, and this is where a simple rule turns into a fiddly one.
A fund passes the state exemption through only in proportion to how much of its income came from US government obligations. If a fund derived 78% of its income from Treasuries, then 78% of the distribution you received is exempt on your state return and the rest is not. Fund companies publish this percentage once a year, usually in a tax supplement issued in January or February, and it is the only place the number exists — it is not on the 1099.
Several states add a further condition. California, New York and Connecticut require a fund to hold at least half its assets in US government obligations at each quarter-end before any of the exemption passes through to shareholders. A fund that misses that threshold passes through nothing, even though the underlying interest would have been exempt had you held the bonds directly. A broad aggregate bond fund frequently misses it. A pure Treasury fund does not.
03 TIPS and I bonds have their own timing quirks
Two inflation-linked instruments behave differently enough year to year to be worth separating out, and in both cases the state exemption is the part that stays constant while the federal timing moves.
TIPS adjust their principal with inflation, and that adjustment is federally taxable in the year it happens even though you receive no cash for it until the security matures or is sold. The common name for this is phantom income. It is the standard argument for holding TIPS in a tax-deferred account: the state exemption is no help against a federal bill that arrives before the money does.
I bonds run the other way. Interest accrues inside the bond and the federal tax is deferred until you redeem it or it stops earning, so you choose the year the income lands. The state exemption applies throughout. There is also a separate education exclusion that can make the interest federally tax-free when redeemed for qualified higher education expenses, subject to income limits that phase the benefit out.
04 Putting a number on it before you act
The exemption is worth your state marginal rate multiplied by the interest, and that is the whole calculation. On $10,000 of Treasury interest, a Californian near the top of the state schedule keeps several hundred dollars that a corporate bond of identical yield would have handed to Sacramento. A resident of Florida, Texas or Washington keeps nothing extra, because there was no state income tax to avoid.
That makes this a tiebreaker rather than a strategy. If a Treasury and a comparable CD or corporate bond offer similar yields and you live in a high-tax state, the Treasury wins on after-tax terms. If the corporate bond pays materially more, the exemption may not close the gap — and in a no-income-tax state it closes none of it.
The one place it does change behaviour is asset location. Because the exemption is only useful in a taxable account, holding Treasuries in a taxable brokerage account and higher-yielding taxable bonds inside an IRA is usually the better arrangement of the same portfolio. That is a decision about which account holds what, not about what you own.
Shows: how much state and local income tax the Treasury exemption saves you in a year, including the reduction when the holding sits inside a fund that is only partly invested in government obligations. Ignores: federal tax on the same interest, state thresholds that can block the pass-through entirely, and any difference in yield between the investments you are comparing.
Source: Treasury bonds
I spent longer than I want to admit comparing a Treasury fund against a CD on quoted yield alone, in a year when I was resident somewhere with a real state income tax. The two looked within a few basis points of each other and I picked on convenience. The Treasury was the better after-tax holding by a clear margin, and I had simply left the state exemption out of the comparison, because the quoted yields are the numbers the screen puts in front of you. It is a small lesson with a general shape: the yield you are shown is pre-tax, and which government gets to tax it is part of the yield.
FAQ
Are Treasury bonds exempt from state income tax?
Yes. Interest on Treasury bills, notes, bonds, TIPS and US savings bonds is exempt from state and local income tax. It remains fully taxable as ordinary income at the federal level, and your broker reports the state-exempt portion separately so you can subtract it on your state return.
Does the exemption still apply if I hold a Treasury ETF instead of the bonds?
Partly. A fund passes the exemption through in proportion to the share of its income that came from US government obligations, a percentage the fund company publishes annually. California, New York and Connecticut go further and require the fund to hold at least 50% of its assets in government obligations at each quarter-end before any of it passes through.
Is Treasury interest also exempt from federal tax?
No, and this is the most common misunderstanding. Only municipal bonds carry a general federal exemption. Treasury interest is ordinary federal income; the exemption runs the other way, protecting it from state and local tax instead.
Sources
Regulator references
- Topic no. 403, Interest received · Internal Revenue Service · 2025How interest income is reported and which categories are federally taxable.Last verified: 2026-09-07
- Publication 550, Investment Income and Expenses · Internal Revenue Service · 2025The detailed treatment of Treasury obligations, savings bonds and fund distributions.Last verified: 2026-09-07
- Treasury bonds · U.S. Department of the Treasury · 2025Terms of marketable Treasury bonds and their state and local tax status.Last verified: 2026-09-07
- Treasury Inflation-Protected Securities (TIPS) · U.S. Department of the Treasury · 2025How the inflation adjustment to principal works, which drives the phantom-income timing.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.