We are adding a new subpart to our regulations, which contains the rules we will apply to determine the income-related monthly adjustment amount for Medicare prescription drug coverage premiums. This new subpart implements changes made to the Social Security Act (Act) by the Affordable Care Act. These rules parallel the rules in subpart B of this part, which describes the rules we apply when we determine the income-related monthly adjustment amount for certain Medicare Part B (medical insurance) beneficiaries. These rules describe the new subpart; what information we will use to determine whether you will pay an income-related monthly adjustment amount and the amount of the adjustment when applicable; when we will consider a major life- changing event that results in a significant reduction in your modified adjusted gross income; and how you can appeal our determination about your income-related monthly adjustment amount. These rules will allow us to implement the provisions of the Affordable Care Act on time that relate to the income-related monthly adjustment amount for Medicare prescription drug coverage premiums, when they go into effect on January 1, 2011.