A CPA Plans Separate 2026 Returns to Help Cover Her Medical Bills, but That Choice Could Trigger a $6,355 Medicare Surcharge for Him in 2028

A retired couple’s accountant found a tax strategy that could erase her medical expenses on their return, but it also sets up a Medicare cost increase two years later that neither spouse had anticipated.

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Consider a hypothetical retired couple who both receive Medicare. He has $140,000 in modified adjusted gross income (MAGI) from a pension and IRA withdrawals, while she has $60,000 and paid a sizable amount of uncovered medical costs out of pocket. Their CPA recommends filing separate 2026 returns so her expenses can clear the medical deduction threshold against her lower income. From his perspective, Medicare seems safe because the couple’s combined $200,000 is below the $218,000 joint threshold for the income-related monthly adjustment amount, or IRMAA.

That calculation changes once he files separately. Roughly 8% of Part B beneficiaries pay an income-related surcharge, and couples who file jointly while staying well below $218,000 are generally outside that group. A separate filing can push a moderate-income retiree into it.

How Medicare Uses the Tax Return

Social Security determines IRMAA from adjusted gross income plus tax-exempt interest, so municipal bond income is included. The system looks back two years, which means the 2026 return affects 2028 premiums. The Centers for Medicare & Medicaid Services (CMS) also has a separate three-tier table for married couples who file separately and lived together at any point during the tax year.

If his MAGI stays at or below $109,000, he would owe only the standard $202.90 Part B premium. Cross that line by a dollar, and the premium rises to $649.20. That is the same premium a single filer would face only with income above $205,000. Under a joint return, the couple’s $200,000 keeps both spouses at the standard $202.90 premium.

The Price of Filing Separately

At 2026 rates, his Part B surcharge would total $5,355.60 per year. Adding Part D brings another $999.60, for a combined annual Medicare hit of $6,355.20. She would owe no surcharge at $60,000 in MAGI. Those figures represent the couple’s added yearly Medicare cost under current rates, though the actual 2028 amounts have not yet been released.

Form SSA-44 does not solve this problem afterward. It can lower IRMAA only after a qualifying life event, such as a spouse’s death, a divorce, or a work stoppage. Choosing a filing status does not qualify.

Balancing the Tax Break Against the Premiums

Under federal rules, taxpayers may deduct medical expenses that exceed 7.5% of adjusted gross income. For them, the joint-return threshold would be $15,000, while her separate-return threshold would be $4,500. However, that deduction does not reduce the income figure Medicare uses to set IRMAA.

Filing separately could increase her medical deduction by as much as $10,500, assuming she has enough eligible expenses. At an illustrative 22% tax rate, that would save about $2,310 in taxes, but it would come with an extra $6,355.20 in Medicare premiums. Before any other tax effects, that leaves a gap of $4,045.20.

Separate returns can also create other drawbacks. If she itemizes, his standard deduction falls to zero. The newer senior deduction of up to $6,000 per eligible person also requires a married couple to file jointly.

At this income level, the medical deduction alone is unlikely to offset his Medicare surcharge. Separate filing may still work for other tax reasons, but the CPA should compare the couple’s total tax bill and premium costs. Retirees often run into premium traps when they optimize one part of the return and overlook the other, and a free Medicare guide explains more of them.

Questions to Ask the CPA Before Filing

1. “Show both returns with the 2028 Medicare premiums added in.” Ask for the full tax difference between filing jointly and separately, including the loss of the standard deduction and senior deductions. Then subtract $6,355.20. If the separate return still does not come out ahead, file jointly.
2. “Can my separate MAGI be reduced to $109,000 or less?” Ask whether IRA withdrawals can be shifted to another year or whether tax-exempt interest is pushing his income over the limit. Staying just under the threshold avoids the surcharge entirely. Going over by even one dollar triggers the full $6,355.20.
3. “If we already filed separately, can we change it?” Married couples can switch separate returns to a joint return for up to three years after the original filing deadline. Social Security can then recalculate IRMAA using the amended return, along with IRS confirmation or a transcript. The request must be made within the agency’s three-calendar-year window.