Optional Redemption 

A right to retire an issue or a portion thereof prior to the stated maturity thereof during a specified period of years. The right can be exercised at the option of the issuer or, in pass-through issues, of the primary obligor. ?Optional redemption? usually requires the payment of a premium for its exercise, with the amount of the premium decreasing the nearer the option exercise date is to the final maturity date of the issue.