Medicare Late Enrollment Penalties and IRMAA Appeals

The three penalties

Medicare has three late enrollment penalties, and they behave differently enough that it is worth taking them one at a time.

Part B. Your initial enrollment period is a seven-month window around your 65th birthday: the three months before, the month itself, and the three months after. If you do not enroll then and do not have qualifying coverage that lets you delay, the premium increases by a percentage for each full twelve-month period you could have had Part B and did not. That increase generally stays for as long as you have Part B, which for most people means the rest of their life.

Part D. If you go 63 days or more in a row without Part D or other creditable prescription drug coverage after your initial enrollment period ends, a penalty accrues for every full month of the gap. It is calculated against a national base premium that changes annually and is added to your Part D premium for as long as you have Part D coverage.

Part A. Most people qualify for premium-free Part A through their own or a spouse's work history, and for them there is no Part A penalty. If you have to buy Part A, a late penalty applies, but unlike the other two it is time-limited: it lasts for twice the number of years you could have had Part A and did not sign up.

Current employment, precisely

The exception everyone relies on is real, and it is narrower than people assume.

If you or your spouse are still working and you are covered by a group health plan based on that current employment, you can generally delay Part B past 65 without a penalty. When that employment or that coverage ends, whichever comes first, a special enrollment period of eight months begins. Enroll inside it and no penalty applies. Miss it and the clock that would have been paused is treated as having been running.

Two details catch people. The first is employer size: where the employer has fewer than twenty employees, Medicare generally becomes the primary payer at 65, and the group plan may expect you to have Part B in place. The second is that "based on current employment" means exactly that. Coverage you keep after the job ends is not the same thing, however similar the insurance card looks.

Drug coverage follows a separate test: whether it is creditable, meaning expected to pay at least as much as standard Part D. Your plan is required to tell you in writing each year.

The COBRA trap

This is the single most common way people end up with a permanent Part B penalty, and it happens to careful people.

Someone past 65 retires, elects COBRA to keep the same doctors and the same card, and plans to move to Medicare when COBRA runs out. It feels like continuous coverage, and in the sense of paying claims it is. But the eight-month special enrollment period started when the job ended, not when COBRA ends. If COBRA runs eighteen months, the window closed ten months before it.

The practical rule is simple. If you are 65 or older and your employment is ending, treat the last day of work as the date that matters for Part B, and decide about COBRA separately. The two are compatible, but the enrollment decision cannot wait for COBRA.

The HSA trap

Health savings accounts create a second, quieter problem at the same moment.

Once you are enrolled in any part of Medicare, including premium-free Part A, you can no longer contribute to an HSA. That is straightforward. What is less obvious is that when you enroll in premium-free Part A after turning 65, the coverage is generally backdated up to six months, though not to before the month you turned 65. Applying for Social Security at or after 65 enrolls you in Part A automatically, with the same backdating.

The consequence is that HSA contributions made in the six months before you applied can become excess contributions after the fact. The usual response is to stop contributions roughly six months before you plan to enroll or claim, and to have your CPA review any contributions made in that window. Money already in the HSA remains yours to use for qualified expenses, including many Medicare premiums.

Appealing IRMAA when you retire

The income-related monthly adjustment amount raises Part B and Part D premiums for households above set income thresholds, using the tax return from two years earlier. We cover how withdrawals and conversions move you between those tiers in coordinating income, Medicare, and investments. This section is about what happens in the first year or two of retirement, when that two-year lookback works against you.

If you retire at 65 or later, Social Security will set your first Medicare premiums from a year when you were still drawing a full salary. Your income may have fallen sharply since, but the surcharge reflects the old figure.

Social Security recognizes this. Form SSA-44 lets you request a new determination based on a more recent year's income if you have had a qualifying life-changing event. The listed events include work stoppage and work reduction, which is how retirement is described, along with marriage, divorce or annulment, the death of a spouse, loss of income-producing property, loss or reduction of certain pension income, and certain employer settlement payments.

The request is made with documentation of the event and an estimate of the current year's income. If approved, the premium is recalculated. It is one of the few Medicare decisions where a form and an afternoon produce a direct result, and it is routinely overlooked because nobody tells new retirees it exists.

A separate route exists if Social Security used incorrect or outdated tax information: that is a request for reconsideration rather than a life-changing-event request, and it follows a different process.

Putting the dates in order

Almost everything on this page reduces to getting a handful of dates right and in the right order. For most households approaching 65, the sequence worth writing down is:

• The month you turn 65, which anchors the initial enrollment period.
• The last day of employment-based group coverage, for you and for your spouse, which anchors the eight-month special enrollment period.
• Your Part B start date, which anchors the Medigap open enrollment window, covered in Medicare Supplement planning before you retire.
• The date you plan to claim Social Security, which can trigger Part A and ends HSA eligibility.
• Your first year of Medicare premiums, which is the year to consider an SSA-44 request if your income has dropped.

Richard Casolari, Financial Advisor, Investment Advisor Representative, CFP®, has spent roughly fifty years in financial services. The practice is founder-led and based in Palos Heights, and the work coordinates Medicare enrollment and supplement timing, retirement income planning, tax-aware withdrawal sequencing in coordination with your CPA, and protection planning through licensed affiliates, into one written plan.