1. Portion of the monthly capitation payment to physicians retained by the health maintenance organization (HMO) until the end of the year to create an incentive for efficient care. If the physician exceeds utilization norms, he or she will not receive it. Also called withhold incentive . 2. Percentage of payment or set dollar amounts that are deducted from the payment to the physician group/physician that may or may not be returned depending on specific predetermined factors.