A Treasury Bill (T-Bill) is a short-term debt obligation issued by the U.S. government with a maturity of less than one year. T-Bills are sold in denominations of $1, 000 and are auctioned off at a discount from face value. They are attractive investments because they offer a guaranteed return and are exempt from state and local taxes. T-Bills are considered to be one of the safest investments available and are often used as a hedge against inflation.