About Treasury Marketable Securities
The federal government finances its operations in part by selling various types of securities. All these securities are backed by the full faith and credit of the United States government.
"Marketable" means you can transfer the security to someone else, and you can sell the security before it matures (reaches the end of its term).
The United States Treasury offers five types of Treasury marketable securities: Treasury Bills, Treasury Notes, Treasury Bonds, Treasury Inflation-Protected Securities (TIPS), and Floating Rate Notes (FRNs).
Treasury Non-marketable Securities
You can also buy non-marketable U.S. savings bonds from the United States Treasury. They are not marketable because each is registered to one person's Social Security Number. You cannot sell them or transfer them to someone else.