A short-term Treasury bill has recently paid interest in the neighborhood of what a certificate of deposit offers, while the typical savings account at a large national bank has paid a small fraction of a percent. For retirees holding idle cash, the gap is not trivial, and it comes with a tax feature that a bank account cannot match: the interest a Treasury bill earns is exempt from state and local income tax. That combination is why a government IOU that many savers overlook can quietly out-earn the money sitting in a checking-adjacent savings account.
How a Treasury bill actually pays
A Treasury bill is a short-term debt of the federal government, issued in terms as brief as four weeks and as long as one year. Unlike a savings account that credits interest monthly, a bill is sold at a discount to its face value and pays the full face amount at maturity, so the return is the difference between what a buyer pays and what the government returns, as the Treasury explains on its marketable-securities pages. A saver who buys a bill for less than $1,000 and collects $1,000 at the end has earned the spread.
Because bills are backed by the full faith and credit of the United States, they carry no credit risk in the way a corporate bond does, and they can be bought directly and without a fee through the government’s TreasuryDirect platform. The trade-off for that safety is that the yield moves with short-term interest rates set in the market, so the rate available on any given auction is not fixed and can drift up or down between purchases.
Liquidity is the other consideration. A bill is designed to be held to maturity, and while it can be sold early on the secondary market, a saver who needs cash on short notice may prefer to ladder several bills with staggered maturities rather than lock a single lump into one term. That structure keeps a portion of the money coming due every few weeks.
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Where the state-tax break comes in
The feature that separates a Treasury bill from a bank product is the tax treatment of the interest. Income from Treasury securities is subject to federal income tax but is exempt from state and local income taxes, a distinction the Treasury notes directly in its guidance for holders. For a retiree in a state with a meaningful income tax, that exemption effectively lifts the after-tax return above a bank account or CD paying the same headline rate, because the bank interest is fully taxable at both the federal and state level.
The size of that advantage depends entirely on where a saver lives. A resident of a state with no income tax gains nothing from the exemption, while a resident of a high-tax state keeps more of every dollar of bill interest than of the same dollar earned in a savings account. The comparison, in other words, is not one-size-fits-all, and the state-tax angle is a reason to run the after-tax math rather than to assume the bill always wins.
None of this changes the federal side. Treasury interest is reported and taxed at the federal level like other interest income, and TreasuryDirect issues the year-end tax form that documents it. The exemption is specifically a state and local benefit, and it applies to the interest, not to any gain from selling a bill early.
Why the bank comparison is so lopsided
The reason the contrast looks dramatic is that large banks have little competitive pressure to pay much on a basic savings account. The Federal Deposit Insurance Corporation publishes a national average rate on savings deposits that has for a long stretch sat well under 1%, even as short-term government yields ran far higher. A depositor who leaves cash in a big-bank savings account is often accepting a return that trails not only Treasury bills but also online banks and money-market funds.
That does not make a savings account useless. Federal deposit insurance covers up to $250,000 per depositor per bank, the money is available instantly, and there is no maturity to track. A Treasury bill trades some of that immediacy for a higher yield and the state-tax break, which is why the sensible use is often to keep a genuine emergency buffer in insured, instantly available cash and move the surplus that is simply sitting still into bills.
The open question for any individual saver is how much cash is truly idle. Money earmarked for a bill payment next week belongs in the bank; money that has been parked at a fraction of a percent for a year is money working against inflation. The size of that second bucket, and the saver’s own state tax rate, decide whether the Treasury route is worth the extra step.
This article was researched and drafted with the assistance of AI and reviewed by The Money Overview editorial team.
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