What Are Treasury Bills (T-Bills)? A Plain Explainer

Treasury bills, or T-bills, are short-term debt issued by a national government, sold at a discount to their face value and maturing in a year or less. Instead of paying periodic interest the way a typical bond does, a T-bill is sold for less than the amount it will pay out at maturity — the gap between the purchase price and the face value is the return. Buy a bill for $980 that pays $1,000 at maturity, and that $20 difference is the interest, delivered all at once instead of in installments.

How the discount mechanism works

A conventional bond is issued near its face value and pays a stated coupon rate at regular intervals until maturity, when the principal is returned. A T-bill skips the coupon entirely: it’s issued at a discount and simply redeemed at full face value when it matures. The shorter the time to maturity and the lower prevailing interest rates are, the smaller that discount tends to be, since the discount is effectively compensating the buyer for the time value of money over a short, fixed window rather than for ongoing periodic risk.

This structure is why T-bills are quoted and traded a little differently than coupon bonds — their yield is derived from the discount rate rather than from a stated interest payment, and comparing a T-bill’s yield to a coupon bond’s yield requires converting between the two conventions rather than reading the numbers side by side.

Maturities and where T-bills sit in government debt

Government debt is typically issued across a range of maturities, and T-bills occupy the short end — generally maturing in a matter of weeks up to one year. Debt with maturities beyond that, typically running from a couple of years out to a decade or more, is usually issued as notes or longer-dated bonds instead, which do pay periodic coupons. The distinction matters because the short end of the maturity spectrum behaves differently in the market than the long end — it’s more sensitive to near-term central bank interest rate policy and less sensitive to long-run inflation expectations, which is one reason short-term bill yields and long-term bond yields don’t always move together. See what is a yield curve for how the whole maturity spectrum is compared at once, and what is bond duration for why shorter maturities carry less interest-rate risk.

Why T-bills are considered low-risk

T-bills are backed by the issuing government’s ability to raise revenue and, ultimately, to create currency to meet its obligations, which is why they’re widely treated as one of the closest things to a risk-free asset within a given currency — the relevant risk isn’t usually “will this be repaid” so much as broader currency or macroeconomic risk that would affect essentially every asset denominated in that currency. That perceived safety, combined with a deep and liquid secondary market, is why T-bills are commonly held as a cash-equivalent by institutions, money market funds, and conservative individual investors who want a place to park cash briefly without taking on meaningful price risk.

T-bills vs money market funds vs CDs

A money market fund often holds T-bills directly, among other short-term instruments, and offers a way to get similar exposure with daily liquidity and diversification across many issues, in exchange for a management fee and slightly more counterparty complexity than holding a bill directly. A certificate of deposit locks up cash with a bank for a fixed term at a fixed rate, backed by deposit insurance up to a limit rather than by government debt directly, and typically penalizes early withdrawal — a real tradeoff against a T-bill, which can usually be sold on the secondary market before maturity if cash is needed early, at whatever price the market is currently offering.

	T-bill	Money market fund	CD
Issuer	National government	Fund manager (holds various instruments)	Bank
Return mechanism	Discount to face value	Fund yield, net of fees	Fixed interest rate
Typical term	Weeks to one year	No fixed term (redeemable daily)	Fixed term, penalty for early exit
Liquidity before maturity	Sellable on secondary market	High — redeemable daily	Low — often penalized
Primary risk	Minimal credit risk	Slightly higher (fund-level, diversified)	Bank-specific, within insurance limits

The takeaway

A Treasury bill is short-term government debt sold at a discount to its face value, with that discount serving as the return instead of a periodic coupon payment. Its short maturity and low perceived credit risk make it a common place to hold cash conservatively, and it sits alongside money market funds and CDs as one of a few standard short-term options — the main tradeoffs between them come down to liquidity, fees, and exactly what’s backing the return.