Some bonds have a call feature. This feature is designed to give the issuer more control over its debt. A call feature gives the issuer the right to redeem, or call, the bonds at a certain price at a certain date in the future as specified in the initial bond offering.
Usually, the call feature requires the bond issuer to pay a premium to the original face value of the bond as compensation to the investor for redeeming the bond early. However, there is no obligation on the part of the issuer to call the bond. Therefore, the issuer has all of the control regarding triggering the call feature and is thus likely to do so only if it is advantageous to the company instead of the investor.