Bond investors reduce interest rate risk by buying bonds that mature at different dates. For example, say an investor buys a five-year, $500 bond with a 3% coupon. Then, interest rates rise to 4%. The investor will have trouble selling the bond when newer bond offerings with more attractive rates enter the market. Interest Rate Risk Interest rate risk is the risk that changes in market interest rates will affect the value of bonds and other debt instruments. The changes in market interest rates may arise due to multiple factors: changes in Federal Reserve policy, movement in yield curve due to overall economic outlook, etc. A risk-free rate of return formula calculates the interest rate that investors expect to earn on an investment that carries zero risks, especially default risk and reinvestment risk, over a period of time. It is usually closer to the base rate of a Central Bank and may differ for the different investors.