US Treasury Securities are the US Treasury issued debt instruments, also known as Treasury Bonds, Notes, and Bills. These obligations are backed by the "Full Faith and Credit of the US Government".
Treasury Bill - short-term debt obligation usually with maturities of less than one year, sold in denominations of $1000.
Treasury Notes - A marketable U.S. government debt security with a fixed interest rate and a maturity between one and 10 years. Treasury notes can be bought either directly from the U.S. government or through a bank.
Treasury Bond - A marketable, fixed-interest U.S. government debt security with a maturity of more than 10 years. Treasury bonds make interest payments semi-annually and the income that holders receive is only taxed at the federal level.