Treasury Bill (T-Bill)

A Treasury bill is short-term US government debt with a maturity of one year or less, sold at a discount to its face value rather than paying a periodic coupon: you buy it below par and it matures at par, with the difference being your return.

T-bills became a mainstream retail investment once interest rates rose enough to make their yields competitive with, or better than, many savings accounts, while still carrying the safety of a US government obligation and no state or local tax on the interest earned.