U.S. government-issued debt securities similar to regular savings bonds, except they offer an investor inflationary protection, as their yields are tied to the inflation rate. 

|||Available directly from the U.S. Treasury, these debt securities are an exceptionally low-risk investment suitable for the most risk-averse investor; they have virtually zero default risk and inflationary risk.While relatively risk-free assets such as these usually offer some of the lowest rates of return, it is important to note that I Bonds are usually exempt from income tax. They therefore provide a more attractive after-tax return.