The Income-Related Monthly Adjustment Amount (IRMAA) is an amount you may pay in addition to your Part B or Part D premium if your income is above a certain level. The Social Security Administration (SSA) determines if you owe an IRMAA based on the income you reported on your IRS tax return two years prior. If you are expected to pay IRMAA, SSA will notify you that you have a higher Part B or Part D premium. If you have had certain life changing events in the past two years, you can ask for a new assessment.