"Under §1839(i)(5) [of the Social Security Act], the dollar amount for the income tiers will be adjusted annually based on the Consumer Price Index. However, in accordance with §3204 of the Affordable Care Act, these income threshold amounts will remain at the 2010 levels for calendar years 2011-2019."And as noted by the Social Security Administration (SSA):
"If you have higher income, the Medicare law requires an adjustment to your monthly Medicare Part B (out-patient medical insurance) and Medicare prescription drug coverage premiums (Medicare Part D). Higher-income beneficiaries pay higher premiums for Part B and prescription drug coverage. This [additional premium cost] affects less than 5 percent of people with Medicare, so most people do not pay a higher premium."
"Changes in the law affect how Medicare prescription drug coverage premiums are calculated for those with higher incomes. Beginning January 1, 2011, if you have a higher income, you will pay a higher premium for your Medicare prescription drug coverage (Part D). If your income is $85,000 or above (individual) or $170,000 or above (married filing jointly), you must pay an extra premium amount for your Medicare Part B and Medicare prescription drug coverage [Medicare Part D]. This extra premium amount is called the income-related monthly adjustment amount (IRMAA). This amount is based on your modified adjusted gross income as reported on your IRS tax return from 2 years ago (your most recent tax return)."
"By law, income-related monthly adjustment amount (IRMAA) for prescription drug coverage must be withheld from Social Security [SSA], Railroad Retirement Board [RRB], or Office of Personnel Management [OPM] benefit checks unless the monthly payment isn’t enough to cover the entire amount owed. If your check isn’t enough to cover the entire amount, you will get a bill from Medicare."What law established Medicare Part D IRMAA?