Treasury Bill
Definition
A short-term government debt security, generally maturing in one year or less. It is typically sold below its face value and repaid at face value at maturity.
United States
How does a U.S. Treasury bill earn interest?
A bill can sell below its face value and pay face value at maturity. If you pay $990 and receive $1,000 at maturity, the $10 difference is your earnings before taxes. An annualized yield also accounts for how long you held it.
TreasuryDirect Treasury bills