Section 418.2101 - What is the income-related monthly adjustment amount?(a) The income-related monthly adjustment amount is an amount that you will pay in addition to the Medicare prescription drug coverage plan monthly premium, plus any applicable increase in that premium as described in 42 CFR 423.286 , for your Medicare prescription drug coverage plan when your modified adjusted gross income is above the threshold described in § 418.2105 .(b) Your income-related monthly adjustment amount is based on your applicable modified adjusted gross income as described in § 418.2115 and your tax filing status.(c) We will determine your income-related monthly adjustment amount using the method described in § 418.2120 .