In property insurance, requires the policyholder to carry insurance equal to a specified percentage of the value of property to receive full payment on a loss. For health insurance, it is a percentage of each claim above the deductible paid by the policyholder. For a 20 percent health insurance coinsurance clause, the policyholder pays for the deductible plus 20 percent of his covered losses. After paying 80 percent of losses up to a specified ceiling, the insurer starts paying 100 percent of losses.