Imagine this: you sell your business in a banner year, retire comfortably at 65, sign up for Medicare — and then a letter arrives saying your monthly premiums are hundreds of dollars higher than the standard amount. Not because of anything you earned this year, but because of what you earned two years ago. Welcome to IRMAA, the surcharge that turns your best earning years into your most expensive Medicare years.
IRMAA — the income-related monthly adjustment amount — is extra premium tacked onto Medicare Part B and Part D for higher-income enrollees. Most employees first meet it as an annoyance. Business owners meet it as a planning problem, because lumpy income — a business sale, a big equipment disposition, a large Roth conversion, a banner K-1 year — is exactly what pushes people over IRMAA's cliffs. The good news: once you understand the two-year lookback, the brackets, and the appeal process, you can plan around most of the damage.
What IRMAA Is and Why It Surprises Business Owners
Medicare Part B has a standard monthly premium — $202.90 per person in 2026. If your income is above a threshold, Social Security adds a surcharge to Part B and another to Part D. These surcharges are IRMAA. They apply whether you have original Medicare or a Medicare Advantage plan, and each spouse pays their own — a married couple pays every surcharge twice.
Three features make IRMAA uniquely painful for owners:
The two-year lookback. Your 2026 premiums are set by your 2024 tax return. The 2024 income that felt like a triumph — the sale proceeds, the record profit — shows up as a premium bill in 2026, often the first year you're actually living on less. There is no mechanism that automatically uses current income; the system always reaches two years back unless you successfully appeal.
Cliffs, not phase-ins. IRMAA has five tiers, and crossing a threshold by a single dollar triggers the entire tier's surcharge. A couple filing jointly with $218,001 of 2024 income pays the full first-tier surcharge — roughly $2,300 a year extra for the household — while a couple at $218,000 pays nothing extra. There is no proration and no rounding mercy.
MAGI counts more than you think. IRMAA uses a special modified adjusted gross income: your adjusted gross income plus tax-exempt interest and a few rarer add-backs. That means municipal-bond interest — the income you bought specifically because it was "tax-free" — counts toward IRMAA. So do capital gains, Roth conversions, required minimum distributions, and the gain on selling your business or a rental property. Itemized deductions do not reduce MAGI. A standard cash charitable deduction does not reduce it either.
The 2026 Brackets: Know Exactly Where the Cliffs Are
For 2026 coverage, Social Security looks at MAGI from your 2024 return. Here are the tiers, with the total monthly Part B premium per person and the monthly amount added to your Part D plan premium:
| 2024 MAGI (single) | 2024 MAGI (joint) | Part B per month | Part D add-on per month |
|---|---|---|---|
| $109,000 or less | $218,000 or less | $202.90 (standard) | $0 |
| $109,001–$137,000 | $218,001–$274,000 | $284.10 | $14.50 |
| $137,001–$171,000 | $274,001–$342,000 | $405.80 | $37.50 |
| $171,001–$205,000 | $342,001–$410,000 | $527.50 | $60.40 |
| $205,001–$499,999 | $410,001–$749,999 | $649.20 | $83.30 |
| $500,000 or more | $750,000 or more | $689.90 | $91.00 |
A few things worth noticing. First, the jump from tier to tier is steep: moving from the first to the second tier costs a single filer an extra $121.70 a month for Part B alone. Second, at the top tier a couple pays nearly $14,000 a year above standard premiums — about $11,700 extra for Part B plus about $2,200 extra for Part D. Third, married-filing-separately filers face much harsher thresholds, with the top tier starting at just $391,000 — one more reason to model filing status before you file, not after.
Social Security notifies you by mail with an initial IRMAA determination notice. Read it carefully when it arrives: it states the tax year used, the income figure applied, and your appeal rights. Stuffing it in a drawer is the single most expensive thing you can do with it.
Why Owners Get Hit Harder Than Employees
An employee's income is usually smooth; an owner's income spikes. The spikes that most often trigger IRMAA are all familiar business-owner events:
- Selling the business. The gain lands in one tax year and can vault you several tiers at once — two years before you feel it in premiums.
- Selling a property or large asset. A rental, a warehouse, even appreciated stock sold to fund retirement all count in full toward MAGI.
- Large Roth conversions. Converting in your early 60s is often smart tax planning, but every converted dollar is MAGI in the conversion year — and IRMAA two years later. A $150,000 conversion can easily cost a couple several thousand dollars in added premiums on top of the conversion tax itself.
- Required minimum distributions. Once RMDs begin, they stack on top of Social Security and any other income, and they never stop growing.
- A final banner year of business income. Retiring after your best year ever is the classic trap: peak earnings in the lookback window, fixed income by the time the bill arrives.
The pattern is always the same — one-time income, multi-year premium consequences. Which is why the appeal process matters so much: the most common business-owner scenario, retiring after a high-income year, is precisely the situation the appeal was built for.
The SSA-44 Appeal: When a Life-Changing Event Resets the Clock
If your income has fallen since the lookback year because of a qualifying life-changing event, you can ask Social Security to base IRMAA on a more recent year instead. The request is made on Form SSA-44, filed with your local Social Security office, with evidence of both the event and your lower current income (a recent return, pay stubs, or similar documentation).
The qualifying events are specific and limited:
- Work stoppage — you or your spouse stopped working, including retirement
- Work reduction — hours or pay cut back
- Marriage, divorce or annulment
- Death of a spouse
- Loss of income-producing property
- Loss or reduction of certain pension income
- Employer settlement payment
Notice what retirement after selling a business maps to: work stoppage. A former owner whose premiums reflect a sale year but whose current income is lower has a legitimate, purpose-built path to lower premiums. Document the retirement date, show the current-year income, and file.
Equally important is what does not qualify. A drop in investment income alone — smaller Roth conversions this year, market losses, a down year in the business you're still running — generally does not support an appeal without one of the listed events. Neither does simply feeling that the surcharge is unfair relative to your current wealth. If no qualifying event occurred, your remedy is planning, not paperwork: getting MAGI under control for future lookback years.
File promptly after you receive the determination notice, keep copies of everything, and follow up — if the appeal is denied, the notice explains further review rights. And remember that IRMAA is recalculated every year, so a successful appeal for one year does not permanently settle anything; each year's premiums stand on their own lookback year.
Planning Ahead: Managing MAGI Two Years Out
Because the lookback is always two years, IRMAA planning is really income-timing discipline starting around age 63 — the year whose return sets your first Medicare premiums at 65. Strategies worth modeling with your tax advisor:
Map every big income event to its premium year. Before you schedule a business sale, a property disposition, or a large Roth conversion, write down which Medicare year it will affect and which tier it pushes you into. Sometimes shifting a closing by a few weeks across year-end moves the surcharge into a year you'd rather absorb it — or spreads one spike across two lookback years instead of stacking it into one.
Fill brackets deliberately, not accidentally. If Roth conversions make sense for you, convert up to — but not $1 over — an IRMAA threshold. Because the tiers are cliffs, the marginal cost of the dollar that crosses a line can be thousands in premiums. Leave yourself a buffer for late-arriving 1099 corrections and surprise K-1 income.
Use qualified charitable distributions. Once you're 70½ or older, directing IRA distributions straight to charity (up to the inflation-adjusted annual limit, about $111,000 in 2026) satisfies required minimum distributions without the money ever entering your MAGI. For a charitably inclined owner, it is the single most efficient IRMAA lever available — unlike a regular cash donation, which does not reduce MAGI.
Watch what counts. Tax-exempt interest counts. Capital gain distributions from mutual funds count. The taxable portion of Social Security counts. Anything that raises AGI without you "feeling" richer deserves a second look in November, while you can still act — harvesting losses, deferring invoices into January if you're on the cash method, or accelerating deductible business expenses.
Coordinate spouses. Both spouses pay IRMAA individually, but the thresholds apply to combined MAGI on a joint return. In the years that set premiums, every household income decision — whose account to draw from, whose name is on the asset sale — is a joint MAGI decision.
Where Your Books Come In
Here is the part owners overlook: every number that sets your IRMAA already lives in your bookkeeping. MAGI is built from the same income your books track — revenue timing, asset sale gains, retirement-plan contributions that reduce AGI, health-savings-account contributions, the estimated-tax payments that signal where the year is heading.
Owners who keep clean, current books can project their MAGI in October, while there is still time to defer income, accelerate expenses, bunch a conversion, or hold an asset sale for January. Owners who reconstruct the year in April get no such chance — the lookback year is already locked, and the premium bill is already written. Separating one-time income (sales, conversions, bonuses) from recurring operating income in your chart of accounts makes these projections dramatically easier, because IRMAA planning is almost entirely about isolating and timing the one-time spikes.
Keep the records that support an appeal, too: the dated retirement or hours-reduction letter, the sale closing statement, the year-over-year income comparison. An SSA-44 supported by organized documentation moves faster than one assembled from a shoebox.
Simplify Your Financial Management
IRMAA rewards the owner who knows their numbers two years ahead — and punishes the one who meets their accountant in April. Beancount.io provides plain-text accounting that gives you complete transparency and control over your financial data, so projecting MAGI, timing big income events, and documenting an appeal is a matter of querying your own books, not reconstructing them. Get started for free and see why developers and finance professionals are switching to plain-text accounting.
