Interest earned on all U.S. Treasury securities, including Treasury bills (T-Bills), is exempt from taxation at the state and local level but is fully taxable at the federal level. Following the end of the tax year, in January of the new year, owners of Treasury bills should receive a Form 1099-INT from the Department of the Treasury. This form details how much interest was earned on government securities for the year—information that is also filed with the Internal Revenue Service (IRS).
Key Takeaways
- Interest from Treasury bills (T-bills) is subject to federal income taxes but not state or local taxes.
- The interest income received in a year is recorded on Form 1099-INT.
- Investors can opt to have up to 50% of their Treasury bills' interest earnings automatically withheld.
- If you live in a state that charges a high income tax, T-bills might be more advantageous than other short-term fixed instruments, like CDs.
Understanding Treasury Bills (T-Bills)
But first, a quick recap of the asset. Treasury bills are short-term debt obligations that are fully backed by the faith and credit of the U.S. government. They are sold in denominations of $100 up to $10 million. T-bill maturity durations are one calendar year or less. Six maturity durations are offered: 4, 8, 13, 17, 26, and 52 weeks.
Like all Treasury securities, T-bills are considered to be risk-free assets. The likelihood of the U.S. government defaulting on debt obligations is incredibly low, given its ability to tax and print money and, of course, the general strength and reputation of the U.S.
It was this reputation for safety that, during the 2007-2008 financial crisis, caused investors to flock to Treasury securities as losses in stocks and other assets in their portfolios mounted. Those who had already invested heavily in Treasury securities prior to the crisis did successfully safeguard their capital.
Tax Rate of Treasury Bills
The interest earned by a T-bill is taxable as investment income in the year the interest was received. It must be reported on your federal tax return, Form 1040, and is taxed at the investor's marginal tax rate.
Even if you don't receive a Form 1099-INT for some reason, you are responsible for reporting the interest income generated by your T-bills and paying taxes on that amount.
If you buy a T-bill and then sell it for a profit, that profit will be taxable as a capital gain.
Paying federal taxes on T-bills can be simplified with tax withholding. Investors who own Treasury bills can opt to have up to 50% of their interest earnings automatically withheld; the exact percentage can be specified through any retail securities site. The Treasury automatically transfers the withholdings to the U.S. Internal Revenue Service (IRS) and reports the amount that is withheld on the 1099-INT form.
Tax Advantages of T-Bills
Although T-bills don't pay the highest interest rate (the tradeoff for being so low-risk), their exemption from state and local taxes can give them an advantage over other short-term, fixed-income assets, such as certificates of deposit (CDs)—especially for investors living in high-income-tax states, such as California, Hawaii, New York, and Oregon. CDs are fully taxable.
To compare the interest rate from a CD with the rate from a Treasury bill and see which works out better tax-wise, you have to calculate the after-tax yields for both investments.
As an example, say that you are a single taxpayer in Oregon with an income of $100,000 per year, and the one-year Treasury bill you are looking at yields 5.10% (as of June 20, 2024). The federal tax rate for your income level is 24%, and the state income tax rate is 9.9%.
After federal taxes, your net earnings from the Treasury bill will be only 3.876%, or 5.10% x 76%. But the tax rate on the CD is higher since it also includes state taxes.
You would only keep 66.1% of the yields after taxes (100% - 24% - 9.9%). Divide 3.876%, the after-tax yield of the Treasury bill, by 66.1% to get 5.86%, the equivalent after-tax yield for a certificate of deposit. A CD must therefore yield more than 5.86% to be a better deal than the Treasury at your income level.
Correction—June 9, 2022: An earlier version of this article incorrectly calculated the equivalent yields between Treasuries and CDs.
