Key Takeaways

• Medicare Part D IRMAA letters notify you of an income-based Medicare prescription cost increase and require your attention.
• Review the information, verify your income, and know how to request changes or seek support—especially after the PSHB transition.

If you’ve received a Medicare Part D IRMAA letter in the mail, you may feel confused or uneasy—especially with the recent transition from FEHB to PSHB for postal retirees. This guide will help you break down each section of the letter, explain its impact on your prescription costs, and outline the steps you can take next.

What Are Medicare Part D IRMAA Letters?

Purpose of the IRMAA letter

The Income-Related Monthly Adjustment Amount (IRMAA) letter is an official notice informing you that, based on your income, you must pay an extra amount for your Medicare Part D prescription drug coverage. Medicare law requires this additional charge for individuals whose income surpasses certain limits. This letter explains how much your extra amount will be and when it starts.

Who typically receives these notices

You will usually receive an IRMAA letter if you’re enrolled in Medicare Part D and—according to recent tax returns—your income exceeds specific federal thresholds. For PSHB retirees, the mailing may come during or after the transition from your previous federal health benefits, especially if your current benefits include a Medicare prescription plan.

Why Did I Get This Letter?

Income thresholds that trigger IRMAA

The Social Security Administration checks your tax return from two years ago to determine if your modified adjusted gross income (MAGI) meets or exceeds the federal thresholds. For individual filers and married couples filing jointly, these limits adjust annually. If your income goes beyond these thresholds, you are required to pay the IRMAA fee for Medicare Part D, in addition to your usual plan premium.

Timelines related to PSHB transition

With the PSHB transition officially completed on January 1, 2025, many postal retirees began Medicare coordination through new plan options in 2025 and 2026. If your enrollment in PSHB included a plan with Medicare Part D prescription coverage, your income level could trigger an IRMAA adjustment, resulting in the postal IRMAA letter you’ve recently received.

How Does IRMAA Affect PSHB Retirees?

Coordination with PSHB prescription benefits

After shifting from FEHB to PSHB, your prescription drug coverage may be integrated with Medicare Part D if you’re Medicare-eligible. While the core prescription benefits from PSHB plans remain, the IRMAA charge is a separate monthly cost paid directly to Medicare or through Social Security withholding for Part D. The PSHB plan itself doesn’t charge or collect the IRMAA.

Implications for monthly Medicare costs

The IRMAA is in addition to any plan premium and what your PSHB drug coverage would otherwise cost. This means you have to pay both your standard premium (if any) and the IRMAA on top of that. Failing to pay the IRMAA could eventually result in a loss of your Medicare Part D prescription drug coverage, which can also affect how your PSHB prescription benefit works. So it’s important not to ignore the letter and resolve any issues right away.

What Does the IRMAA Letter Include?

Key information to review

When you open your IRMAA letter, pay close attention to:

• The tax year used for your income determination (usually two years prior)
• The calculated income bracket and monthly IRMAA amount
• Your Medicare identification details
• The date the IRMAA charge will begin
• Instructions for what to do if your income has recently changed

Common terms explained in plain English

• IRMAA: Income-Related Monthly Adjustment Amount—an extra cost tied to your Medicare prescription coverage based on income.
• MAGI: Modified Adjusted Gross Income—the figure Social Security uses to decide your IRMAA level.
• Effective date: The day your extra charge starts.
• Reconsideration: The appeal process if you think your IRMAA was calculated incorrectly or your income has dropped.

Steps to Take After Receiving a Letter

Verifying your income information

First, make sure the income Social Security used is correct. Double-check the tax year referenced in the letter and compare it to your own financial records. Errors can happen if, for example, your latest tax filing is different or you experienced a significant life-changing event like retirement or the death of a spouse.

Contacting Social Security or OPM when needed

If you spot an error or life change, contact Social Security promptly. The letter includes contact information and explains how to request a review. If you have questions specific to your PSHB benefits, you can reach out to the Office of Personnel Management (OPM) for clarification on federal retiree coordination, but Social Security makes the final income determination for IRMAA purposes.

Can I Request a Reconsideration?

Situations that may qualify

There are several scenarios that might let you request a new IRMAA calculation, such as:

• Recent retirement (with reduced income)
• Loss of pension income
• Death of a spouse
• Divorce

If your income has decreased because of one of these qualifying events, you may be able to have your IRMAA lowered or removed.

How to submit a request step by step

1. Collect documents that show your change in income—such as your retirement paperwork or revised tax forms.
2. Complete the “Medicare IRMAA Life-Changing Event” form (found at Social Security’s website or local offices).
3. Submit these documents to Social Security by mail or in person.
4. Await Social Security’s final determination and a new notice to confirm any adjustment.

Where Can PSHB Retirees Get Help?

Useful federal resources and official contacts

• Social Security Administration: For IRMAA letters, payments, and reconsideration requests. Visit ssa.gov/benefits/medicare/medicare-irmaa or call 1-800-772-1213.
• Office of Personnel Management (OPM): For general PSHB questions (opm.gov/retirement-services/).
• Medicare.gov: For Medicare Part D information, or to review coverage options and basic requirements.

Trusted private-sector educational organizations

You may also find support from organizations such as State Health Insurance Assistance Programs (SHIPs), nonprofit senior advocacy groups, or independent Medicare education resources. These aren’t insurance agents and don’t sell products, but they can walk you through the IRMAA process in plain language and help explain forms if you’re unsure.