The first is a special Treasury called Treasury Inflation Protected Securities or TIPS. Just like regular Treasurys, TIPS come with different maturities. But with TIPS, the principal of the bond increases with inflation. They start out with the same principal as every other new Treasury, $1,000 per bond. But unlike regular Treasurys, which pay back the same principal of $1,000 at maturity, the principal of TIPS increases by the amount of inflation. If inflation in the second year is 2%, the principal increases to $1,020. The interest rate on TIPS is low, even zero sometimes, but your money is guaranteed to keep pace with inflation.