Debt securities issued by the United States government. Treasury bills normally have maturities of less than one year, while Treasury notes have maturities between one and 10 years, and Treasury bonds have maturities between 10 and 30 years. U.S. Treasury securities are guaranteed by the federal government as to the timely payment of principal and interest. However, if you sell a Treasury security prior to maturity, it could be worth more or less than the original price paid.