A predetermined date and price at which the issuer can redeem the bond prior to its stated maturity. Bonds can be called for many reasons, but a call typically occurs when interest rates drop and issuers are able to obtain lower interest rates to finance their debt. Some bonds are issued as non-callable and subsequently remain in the marketplace until they mature. Knowing all of the possible call or redemption features associated with your bond can help guard against an unexpected return of principal.