Using private insurance claims, the researchers examined (1) prices paid to providers for treating Medicare Advantage enrollees and how these prices compare to those paid for Medicare fee-for-service and commercial patients; (2) the extent to which Medicare Advantage enrollment in a region affects commercial insurance market dynamics and negotiated prices for commercial enrollees; and (3) whether reimbursement generosity in federal Medicare Advantage payments is passed on to providers. The goal of this research was to inform policy discussions of Medicare Advantage provider payment cuts, potential Medicare reforms such as premium support, and potential limits on charges for out-of-network services.