Call Risk
The risk, faced by a holder of a callable bond, that a bond issuer will take advantage of the callable bond feature and redeem the issue prior to maturity. This means the bondholder will receive payment on the value of the bond and, in most cases, will be reinvesting in a less favorable environment (one with a lower interest rate).
Investopedia Commentary
Typically, bond issuers will call a bond because of the high rate they are paying on the bond. If interest rates have declined since it first issued the bonds, issuers will often call the bond once it becomes callable and will create a new issue at a lower rate. The bondholders will then lose out on the high rate of their bond and will have to invest in a lower rate environment.
Related Links
Call Features: Don't Get Caught Off Guard
Bond Basics Tutorial
Advanced Bond Concepts
Advantages Of Bonds
See also: Bond, Callable Bond, Coupon, Interest Rate, Issuer, New Issue, Reinvestment Risk