So, higher interest rates mean lower prices for existing bonds. If interest rates decline, however, bond prices of existing bonds usually increase, which means an investor can sometimes sell a bond for more than the purchase price, since other investors are willing to pay a premium for a bond with a higher interest payment, also known as a coupon. When you buy a bond, an important part of your return is the interest rate that the bond pays. However, yield to maturity is a more accurate representation of the total return you'll get on your investment. Yield to maturity is a figure that incorporates both the bond's interest rate and its price.