A debt instrument under which the issuer promises to pay a specified amount of interest and to repay the principal at maturity. The market value of a bond will fluctuate with changes in interest rates. As rates rise, the value of existing bonds typically falls. If an investor sells a bond before maturity, it may be worth more or less than the initial purchase price. By holding a bond to maturity, an investor will receive the interest payments due plus his or her original principal, barring default by the issuer. Investments seeking to achieve higher yields also involve a higher degree of risk.