What is the term for when a beneficiary shares in the cost of covered expenses?

The term that describes when a beneficiary shares in the cost of covered expenses is co-insurance. Co-insurance typically refers to the percentage of costs that a beneficiary is responsible for after reaching their deductible. For example, if a health insurance plan covers 80% of a medical expense, the beneficiary would pay the remaining 20%, which is their co-insurance share. This system helps to manage healthcare costs by encouraging beneficiaries to consider the costs of healthcare services.

In contrast, the other terms have different meanings: a deductible is the amount a beneficiary must pay out-of-pocket before insurance begins to cover expenses; a premium is the amount paid regularly for health insurance coverage; and an out-of-pocket maximum is a cap on the total amount a beneficiary will spend in a plan year, after which the insurance covers 100% of costs. Thus, co-insurance specifically pertains to shared costs, making it the correct answer in this context.