High-Yield Savings vs. Money Market Account vs. Treasury Bills: Which Pays More on $12,000 Held for 13 Weeks

8 min read · Last updated September 8, 2026

For cash you won’t touch for at least four to thirteen weeks, a Treasury bill bought directly through TreasuryDirect currently pays more than a typical bank account and skips state and local income tax entirely; for cash you might need tomorrow, an FDIC-insured high-yield savings account trades some yield for same-day access.

In this article

• What each option actually is
• How the numbers stack up right now
• The worked math: $12,000 for 13 weeks
• Choose the one that matches your timeline
• Frequently asked questions

Three places exist to park cash you don’t need today but will need soon: a high-yield savings account, a bank money market account, or a 13-week Treasury bill that paid a 3.89% investment rate at its September 8, 2026 auction – and which one actually pays you more depends on a detail most people never check: what state income tax does to each one. Priya Anand faces exactly this choice with $12,000 she set aside in July after selling her car, money she’ll need within six months for a security deposit on a new apartment. On that amount, the gap between the three options is real money.

What each option actually is

A high-yield savings account is a standard FDIC-insured deposit account, just one that pays more than the national average – usually offered by an online-only bank with lower overhead than a branch network. A bank money market account is also an FDIC-insured deposit product, typically requiring a higher minimum balance and sometimes offering limited check-writing, but it is not the same thing as a money market mutual fund, which is a brokerage investment product with no FDIC insurance at all. A Treasury bill is a short-term debt security issued directly by the federal government – you buy it below face value, and it pays you the full face value when it matures in as little as four weeks or as long as 52 weeks.

The FDIC tracks what banks actually pay on both deposit products every week. As of its August 17, 2026 national rate release, the national average savings-account rate sits at just 0.38% APY, and the national average money market account rate at 0.63% APY. Both figures come with a published “national rate cap” of 4.38% APY – the ceiling the FDIC allows a less-than-well-capitalized bank to offer, and roughly the level many competitive online banks price near today.

Buying a Treasury bill directly is simpler than most people expect. TreasuryDirect, the Treasury Department’s own website, lets you open a free account and buy bills in increments as small as $100, with no purchase fee and no broker in between. Bills are auctioned on a fixed weekly or monthly schedule depending on the term – 4-, 6-, 8-, 13-, 17-, and 26-week bills auction weekly, and 52-week bills auction every four weeks – so you don’t place a custom order, you buy into whichever upcoming auction matches the term you want. TreasuryDirect also offers an auto-roll feature that automatically reinvests a maturing bill into a new one of the same term, which turns a single purchase into an ongoing ladder without any manual re-buying.

That ladder idea matters if Priya isn’t fully certain she’ll need all $12,000 on the same date. Splitting the money across a 4-week bill, an 8-week bill, and a 13-week bill instead of buying one 13-week bill means a portion comes due every few weeks – so if the apartment search wraps up early, some of the cash is already accessible without selling anything early on the secondary market at an uncertain price.

How the numbers stack up right now

Factor	High-Yield Savings Account	Bank Money Market Account	13-Week Treasury Bill
Typical yield today	0.38% APY national average; up to ~4.38% at the most competitive online banks	0.63% APY national average; same ~4.38% ceiling	3.89% investment rate at the September 8, 2026 auction
Backing	FDIC-insured up to $250,000 per depositor, per bank	Same FDIC coverage and limit	Backed directly by the US government; no dollar cap
State and local tax	Fully taxable – federal, state, and local	Fully taxable – federal, state, and local	Exempt from state and local income tax; federal tax still applies
Access to your money	Anytime, usually with no penalty	Anytime, sometimes with monthly withdrawal limits	Locked until maturity (4 to 52 weeks); can be sold early on the secondary market, but the price can move against you
Typical minimum to open	Often $0-$100	Often $1,000 or more	$100 through TreasuryDirect, with no purchase fee
Best for	Money you might need with no notice at all	A slightly higher rate than savings, if you can meet the balance minimum	Money you know you won’t need until a set date, especially in a state with real income tax

The worked math: $12,000 for 13 weeks

Say Priya’s online bank pays the FDIC’s published national rate cap of 4.38% APY – close to what several competitive online banks advertise today. Over 13 weeks (91 days), $12,000 at 4.38% APY earns about $131 in interest, before any tax. The 13-week Treasury bill from the September 8, 2026 auction results, at its 3.89% investment rate, earns about $116 over the same 91 days – a lower headline number, but none of it gets touched by state tax.

If Priya lives in a state that taxes interest income at 5%, her after-state-tax savings-account interest drops to roughly $124, still ahead of the Treasury bill’s $116. But the breakeven point is calculable: only once a state’s tax on interest income climbs above roughly 11% does the Treasury bill’s after-tax return actually overtake the savings account’s, a threshold that a handful of the highest-tax states clear. Below that line, the savings account wins even after tax; above it, the Treasury bill does.

Choose the one that matches your timeline

Choose the high-yield savings account if you might need any part of this money on short notice – a job loss, a medical bill, an opportunity you can’t predict. Choose the bank money market account if you want a marginally higher rate than savings plus occasional check-writing, and you’re comfortable meeting a higher minimum balance. Choose the 13-week Treasury bill if you know the date you’ll need the money, you live in a state with a real income tax on interest, and you’re willing to lock the funds – or accept some price risk selling early – in exchange for a rate that state tax can’t touch.

Treasury bill rates move with every auction; the September 8, 2026 result of 3.89% sits within a fairly narrow band of where 13-week bills have priced since June, but a shift in Federal Reserve policy could move the next auction meaningfully. FDIC national averages update monthly and can also drift. Whichever way rates move, the same three-part comparison – headline yield, tax treatment, and how locked-in the money is – still applies.

Frequently asked questions

Is a 13-week Treasury bill riskier than a savings account? No. Treasury bills are backed directly by the US government, the same government that stands behind FDIC deposit insurance. The real difference is access, not safety: your savings balance is available immediately, while a Treasury bill is locked until maturity unless you sell it early on the secondary market.

Do I owe state taxes on Treasury bill interest? No. Treasury bill interest is exempt from state and local income tax, though you still owe federal tax on it. A savings or money market account’s interest is taxed at the federal, state, and local level, which narrows or erases its rate advantage in high-tax states.

What’s the difference between a bank money market account and a money market mutual fund? A bank money market account is an FDIC-insured deposit product, similar to a savings account with occasional check-writing. A money market mutual fund is a brokerage investment product with no FDIC insurance – this article compares only the bank deposit version.

Can I get my money out of a Treasury bill before it matures? Yes, by selling it on the secondary market through a broker or TreasuryDirect, but the price you get depends on how interest rates have moved since you bought it. If you might need cash on short notice, that price risk is the tradeoff for the higher yield.

How much of my money does FDIC insurance actually cover? FDIC insurance covers up to $250,000 per depositor, per insured bank, across each ownership category. A balance above that at a single bank is only insured up to the limit, which is one reason large cash balances sometimes get split across more than one institution.