There are three kinds of government fixed-income securities: Treasury bonds, notes, and bills.

T-bonds (long bonds) mature in 30 years and typically pay the highest interest rates twice yearly. They are sold at monthly online auctions held by the US Treasury in multiples of $100.

T-notes mature anywhere from 2 to 10 years and pay lower yields, also twice yearly.  Like T-bonds, they are sold at auction in $100 increments.

T-bills have the shortest maturity, ranging from four weeks to a year. T-bills are auctioned off to investors at a discount to par (face value). The investor’s return is the difference between the par value and the discount price paid at purchase.