Type of managed care organization (MCO) that will pay for all of the enrollees’ (members’) medical care costs in return for a monthly premium, plus any applicable deductible or copayment. The HMO will pay for all hospital costs (generally referred to as Part A ) and physician costs (generally referred to as Part B ) that it has arranged for and ordered. Like a health care prepayment plan (HCPP), except for out-of-area emergency services, if a Medicare member (enrollee) chooses to obtain services that have not been arranged by the HMO, he or she is liable for any applicable deductible and coinsurance amounts, with the balance to be paid by the regional Medicare fiscal intermediary and/or carrier.