This data note presents new information to help set a context for understanding the implications of recent changes to Medicare’s income-related premiums incorporated in the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA), a new law to repeal and replace Medicare’s Sustainable Growth Rate (SGR) formula for physician payments. It describes current requirements with respect to the income-related premiums under Medicare Part B and Part D, including the number and share of Medicare beneficiaries who are estimated to pay income-related premiums and revenues raised from the income-related premium, based on data from the Centers for Medicare and Medicaid Services (CMS) Office of the Actuary (OACT). It also explains the recently enacted changes in MACRA that will affect some higher-income people on Medicare who are already paying income-related premiums, beginning in 2018.