HYSA vs Treasury Bills: Where Cash Should Sit
Both are places to hold cash you are not investing. A high-yield savings account is a bank deposit; a Treasury bill is a short-term loan to the federal government, bought at a discount and repaid at face value in four weeks to a year.
For most people with an ordinary emergency fund, the savings account is the right answer and the comparison is academic. Two situations flip it: a large balance, and a high state income tax.
Side by side
| High-yield savings | Treasury bills | |
| Backed by | FDIC or NCUA insurance to $250,000 | The U.S. Treasury, no dollar limit |
| Rate | Variable, set by the bank | Fixed at purchase, set by auction |
| Access | Any time, 1–3 days out | At maturity, or sell on the secondary market |
| Federal tax | Yes | Yes |
| State tax | Yes | No |
| Effort | Open an account, transfer money | Buy at auction or through a broker, manage maturities |
The state tax exemption is the real edge
Interest on Treasury securities is exempt from state and local income tax. Bank interest is not. In a state with no income tax that is worth nothing; in a high-tax state it is a meaningful add to the effective yield, and it is the reason a T-bill can beat a savings account paying the same headline rate.
The comparison to run is after-tax, in your own bracket, in your own state. A 4% T-bill and a 4% savings account are not the same product in California and are identical in Texas.
Above the insurance limit
FDIC coverage stops at $250,000 per depositor per insured bank. Treasuries have no equivalent ceiling — they are direct obligations of the federal government. For a cash pile well above the limit, splitting across several banks to stay insured is administrative work that buying bills avoids entirely.
Below the limit, the insurance already does the job and this advantage does not exist.
Where savings wins
A savings account is instantly available, needs no decisions, and pays whatever the market pays without you doing anything. A T-bill has a maturity date: reaching the money earlier means selling on the secondary market, where the price moves with rates and can be below what you paid.
It is also work. Bills mature, and the proceeds sit earning nothing until you buy the next one or set up a rolling ladder. A four-week ladder is thirteen purchases a year. That is fine as a habit and irritating as an obligation.
Which to use
- Emergency fund of any size. Savings. Immediate access is the point.
- Cash you will spend within the year, on a known date. A T-bill maturing just before you need it, or a CD.
- Six figures of cash, high-tax state. T-bills, with the state exemption and no insurance ceiling.
- You would rather not think about it. Savings. The yield difference is smaller than the chance of forgetting to roll a bill.
Related
Mechanics of buying: where to buy U.S. Treasury bills. The deposit-side comparisons: HYSA vs CD and HYSA vs money market.
On the tax side: do you pay tax on savings interest? and federal vs state tax.
Common questions
Are Treasury bills safer than a savings account?
Both are about as safe as dollar assets get. Insured deposits are protected to $250,000 per bank; Treasuries are direct federal obligations with no limit, which matters mainly on large balances.
Do I pay state tax on T-bill interest?
No. Interest on Treasury securities is exempt from state and local income tax, though federal tax still applies.
Can I get my money out of a T-bill early?
Only by selling it before maturity, at the market price, which can be more or less than you paid. There is no penalty as such, but there is price risk.
What is the minimum to buy a Treasury bill?
$100 at auction through TreasuryDirect. Brokers may set their own minimums, often $1,000.
Figures and rules in this article are checked against the official sources below. Where they disagree with us, they win.
