Medicare’s Hidden Two-Year Lookback Rule Catches Retirees Who Inherit IRAs Before 65

A single retiree turns 64, loses her father, and inherits roughly $720,000 in a traditional IRA. She still has a mortgage, still does some consulting on the side, and figures the smartest move is to chip away at the inherited account now, before Social Security starts and her tax picture gets more complicated. So in 2024 she pulled $130,000 from the inherited IRA and wipes out the mortgage. It felt like a clean win. Two years later, her first Medicare bill arrives with a surcharge she never saw coming.

Versions of this scenario pop up routinely in retirement forums. Someone front-loads an inherited account, feels great about being debt-free, and then opens a letter from Social Security explaining their 2026 Part B premium is several hundred dollars a month higher than the standard rate. The real shock is the two-year delay between the decision and the bill.

Why the 2024 Tax Return Sets the 2026 Premium

Medicare’s Income-Related Monthly Adjustment Amount, or IRMAA, is the surcharge layered on top of standard Part B and Part D premiums when modified adjusted gross income (MAGI) clears certain thresholds. The detail that catches most retirees off guard: IRMAA uses a two-year lookback. Your 2026 premium is set by your 2024 tax return.

Run this retiree’s 2024 numbers. The $130,000 inherited IRA distribution counts as ordinary income. Add $52,000 in consulting income, $4,500 in dividends, and $2,500 in interest. Total MAGI lands at roughly $189,000.

For a single filer in 2026, that puts her squarely in the third IRMAA tier, which ranges from $171,001 to $205,000. At that tier, the Part B surcharge is about $325 a month on top of the standard premium, and the Part D surcharge adds another $60 a month. Combined, that is roughly $4,620 in extra Medicare cost for the year, all because her 2024 income briefly crossed a line she did not even know existed.

Here is the part that stings. If she had pulled $110,000 from the inherited IRA instead of $130,000, her MAGI would have landed under $171,000 and dropped her into Tier 2, saving close to $1,700 on 2026 premiums. A $20,000 difference in withdrawal size moved her two tiers in cost.

How the SECURE Act Window Helps

Inherited IRAs from non-spouse parents who died after 2019 must generally be emptied within 10 years. Her deadline is 2033. What many retirees miss is that the law does not require equal withdrawals. She can take nothing for several years and a larger distribution later, or shape every annual distribution around her tax and Medicare picture. That flexibility is the planning tool.

Social Security adds another layer. She has not claimed yet. Once she does, up to 85% of her benefit becomes taxable and flows into MAGI alongside any inherited IRA dollars she pulls. So every withdrawal year after she claims has less room before bumping into the next IRMAA tier. Concentrating bigger distributions in years when other income is lower, and trimming them in years when Social Security and consulting income are both running, is how the ten-year window actually earns its keep.

What to Take Away Before Touching an Inherited Account Near 65

Two ideas matter more than the rest for anyone in this spot:

1. Map the IRMAA tiers before settling on a withdrawal number. The two-year lag means a 2026 or 2027 distribution sets a 2028 or 2029 premium. Knowing where the next threshold sits, and leaving a cushion of a few thousand dollars under it, carries zero downside and can save thousands.
2. Treat the 10-year clock as a dial you adjust each year. The SECURE Act gives you years of flexibility. Pulling a little less now and a little more in a year when consulting income drops or Social Security timing is settled is usually cheaper than front-loading for emotional reasons like clearing a mortgage.

IRMAA resets each year based on the relevant tax return, and many retirees only trip it once. Still, the hardest mistakes to undo in retirement are the ones triggered by a single tax return you cannot rewrite. A quick projection of MAGI against next year’s brackets, ideally before December, is usually all it takes to keep a clean win clean.