We are adding to our regulations a new subpart, Medicare Part B Income-Related Monthly Adjustment Amount, to contain the rules we will follow for Medicare Part B income-related monthly adjustment amount determinations. The monthly adjustment amount represents the amount of decrease in the Medicare Part B premium subsidy, i.e. the amount of the Federal Government's contribution to the Federal Supplementary Medical Insurance (SMI) Trust Fund. This new subpart implements section 811 of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (the Medicare Modernization Act or MMA) and contains the rules for determining when, based on income, a monthly adjustment amount will be added to a Medicare Part B beneficiary's standard monthly premium. These final rules describe: What the new subpart is about; 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.