Definition extracted with permission from American Academy of Family Physicians: Family Physicians and Managed Care
The portion of the monthly capitation payment to physicians withheld by an HMO until the end of the year or other time period to create an incentive for efficient care. The withhold is "at risk". If the physician (or group of physicians) exceeds utilization norms, he does not receive it. It serves as a financial incentive for lower utilization. The withhold can cover all services or be specific to hospital care, laboratory usage, or specialty referrals.