A nonqualified benefit which provides participants a stream of income at retirement. Like deferred compensation, a SERP is an unsecured promise by the employer to provide a retirement benefit to the executive. Most SERP plans provide a percentage of final compensation as a retirement benefit based on age, years of service and compensation at the time of retirement. SERPs can also be designed to provide a fixed level of income to a participant at some later date or it can even be designed as an incentive or performance-based benefit.