Fixed-income debt securities issued by the U.S. government. Treasury securities have no default risk because they are backed by the U.S. government. Treasury bills are securities that mature in less than two years, such as the three- and six-month notes. Treasury notes are securities that mature anywhere from two years to ten years, which includes the two-, three-, five-, and ten-year Treasury notes. The Treasury bond is a security that matures in 30 years.