Medicare Advantage is a type of health insurance that provides coverage within Part C of Medicare in the United States. Medicare Advantage plans pay for managed health care based on a monthly fee per enrollee (capitation), rather than on the basis of billing for each medical service provided (fee-for-service, FFS) for unmanaged healthcare services. Most such plans are health maintenance organizations (HMOs) or preferred provider organizations (PPOs). Medicare Advantage plans finance at a minimum the same medical services as “Original Medicare” Parts A and B Medicare finance via fee-for-service. Part C plans, including Medicare Advantage plans, also typically finance additional services, including additional health services, and most importantly include an annual out of pocket (OOP) spend limit not included in Parts A and B. A Medicare Advantage beneficiary must first sign up for both Part A and Part B of Medicare.