Investors in states like California, New York, and New Jersey can keep every dollar of Treasury bill interest out of their state and local tax returns, a benefit backed by federal statute and confirmed by both the IRS and the U.S. Treasury’s own investor platform. The exemption, rooted in 31 U.S.C. Section 3124, applies to all marketable Treasury securities, including T-bills, notes, and bonds. With more households buying T-bills directly through TreasuryDirect, the tax savings have become a practical consideration for anyone filing in a state that taxes investment income.
Why the state-tax exemption on T-bill interest carries real weight in 2026
The federal law is unambiguous. The text of Section 3124 of Title 31 states that “stocks and obligations of the United States Government are exempt from taxation by a State or political subdivision of a State,” with limited exceptions. That language, confirmed as in effect on June 6, 2026, by the Office of the Law Revision Counsel, means no state or city can impose an income tax on the interest earned from Treasury bills.
The practical difference is sharpest for filers in high-tax states. A resident of a state with a top marginal income-tax rate above 5 percent retains a measurably larger after-tax yield from T-bills than from a comparably yielding corporate bond or certificate of deposit, both of which remain fully taxable at every level. When short-term interest rates are elevated, that spread can add up to hundreds of dollars per year for households with five- or six-figure Treasury positions.
That gap creates a reasonable expectation: once 2025 federal and state filings are fully processed, data on retail T-bill holdings could show higher per-capita ownership in those high-tax states than in the handful of states that charge no income tax at all. No public dataset currently links individual investor ZIP codes to T-bill purchases, so the hypothesis remains untested, but the economic incentive is clear. For many savers, the choice between a taxable bank CD and a state-exempt T-bill with a similar headline yield is effectively a question of whether to leave money on the table.
Federal statute, IRS guidance, and state-level confirmation
Three layers of authority confirm the exemption. First, the statute itself establishes that obligations of the U.S. government are beyond the reach of state and local income taxes except in narrow circumstances. Second, TreasuryDirect’s tax page tells investors that “earnings from Treasury marketable securities are subject to federal tax but exempt from state and local taxes,” explicitly listing bills, notes, bonds, and TIPS. Third, IRS Publication 550 for the 2024 tax year addresses the same rule, specifying that interest from Treasury bills, notes, and bonds is subject to federal income tax but exempt from state and local income taxes.
State tax agencies have independently acknowledged the framework. Massachusetts, for example, issued Technical Information Release TIR 89-8 through its Department of Revenue, applying the federal exemption while carefully distinguishing which instruments qualify as exempt federal obligations and which do not. That distinction matters: not every security issued by a government-related entity counts. Ginnie Mae pass-throughs, Federal Home Loan Bank bonds, and other agency debt may or may not qualify depending on the specific statutory backing, and TIR 89-8 walks through those differences.
Other states follow similar logic in their instructions and bulletins, often tying their definitions of exempt federal obligations back to the same federal statute. In practice, this means that an investor holding a ladder of Treasury bills will generally omit that interest from the state return, while interest from municipal securities issued outside the investor’s home state, corporate bonds, or bank deposits remains fully taxable unless a separate state exemption applies.
What the exemption does not cover
One common misunderstanding deserves correction. The exemption covers state and local income tax only. TreasuryDirect’s own FAQ for individual investors notes that Treasury interest remains exposed to state and local estate, inheritance, gift, and excise taxes. Investors who assume a blanket shield from all state-level taxation could face surprises in estate planning or in states that impose excise-style levies on certain transactions or account balances.
The rule also does not convert Treasury interest into tax-free income at the federal level. For federal purposes, T-bill interest is fully taxable in the year it is received or, in the case of discount bills, when the bill matures or is sold. Investors who buy bills at a discount and hold them to maturity will see the difference between purchase price and redemption value reported as interest income on Form 1099-INT, and that amount must be included on the federal return.
Finally, the exemption does not extend to capital gains. If an investor sells a Treasury note or bond at a profit before maturity, that gain is generally subject to tax at both the federal level and, in most states, the state level. The state-tax break applies to interest, not to trading profits. For buy-and-hold savers who simply roll maturing bills into new issues, this distinction may not matter much, but active traders should not assume that every dollar tied to Treasuries enjoys the same treatment.
For households in states that tax investment income, the combined effect of these rules is straightforward: T-bills offer a way to earn short-term interest that escapes state and local income tax, while remaining fully visible to the IRS and potentially subject to other state levies. As more investors turn to direct purchases through TreasuryDirect and brokerage platforms, understanding where the exemption starts and stops will be essential to accurate tax planning and realistic after-tax return projections.
