Coinsurance is the contractual sharing of covered medical expenses between the insured and the insurer after any applicable deductible has been satisfied. Choice D is correc t. Under a common 80/20 coinsurance arrangement, for example, the insurer pays 80 percent of an eligible expense and the insured pays the remaining 20 percent, up to any out-of-pocket maximum or other plan limitation. Coinsurance reduces premium cost and encourages insureds to consider the cost of care, while preserving significant protection against major expenses. It does not refer to adding family members to a policy, which concerns eligibility or family coverage. It also does not describe insurers sharing risk with each other; that would involve reinsurance or other insurer-to-insurer arrangements. Coinsurance should be distinguished from a deductible, which is a specified dollar amount the insured pays before policy benefits begin. A copayment is instead a fixed dollar amount paid for a covered service. The exact coinsurance percentage, covered-charge definition, network rules, and annual out-of-pocket limit are determined by the policy. Study Guide References/Topics: Policy Provisions, Clauses, and Riders; Medical Expense Insurance; Deductibles and Coinsurance.

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