A guaranteed lifetime annuity is supposed to be the boring, dependable leg of a retirement plan. It arrives on the same day every month and pays regardless of market conditions. For Medicare, though, every dollar of it counts as income. For a 73-year-old whose annuity pays $1,580 a month, that quiet paycheck did something loud: it pushed her Modified Adjusted Gross Income across two Income-Related Monthly Adjustment Amount (IRMAA) thresholds, and her 2026 Medicare Part B bill went up accordingly.
How a $1,580 Check Moves a Medicare Bracket
The standard Part B premium in 2026 is $202.90 per month, up from $185.00 in 2025, with an annual deductible of $283. That is what any single filer with modified adjusted gross income of $109,000 or less pays. Cross that line and IRMAA kicks in. The surcharge jumps in steps rather than scaling gradually.
The 2026 tax brackets for single filers clearly lay out the Medicare Part B premium structure. If your modified adjusted gross income falls between $109,000 and $137,000, you pay $284.10 per month. Move up to the $137,000 to $171,000 range, and that monthly bill jumps to $405.80. Cross into the $171,000 to $205,000 tier, and you are looking at $527.50 each month.
Just two steps above the standard premium lands you at that $405.80 level. In her case, the annuity added $18,960 to her annual income, enough to push her from just beneath the first bracket into the third. On paper, that looks like a modest shift. In practice, it moved her into an entirely different premium tier.
The Real Cost of Two Steps Up
The premium difference between the standard rate and the third tier translates into meaningfully higher annual Part B premiums. Part D IRMAA moves in parallel. At the same MAGI tier, she owes an extra $37.50 per month on top of her Part D plan premium. That is roughly another $450 a year. Combined, the annuity effectively hands back close to $2,900 of its payout to Medicare.
To frame that against a typical retiree budget: the Bureau of Labor Statistics put average annual household expenditures at $78,535 in 2024. The IRMAA surcharge alone is a rounding error against total spending, but it is not trivial against the annuity itself. Roughly 15% of the annual annuity check is absorbed by higher Medicare premiums (IRMAA surcharges alone can add thousands a year, and we mapped the surcharges and coverage gaps that ambush retirees in a free Medicare guide).
Why the Annuity, and Not Some Other Income, Did This
IRMAA is calculated on MAGI from two years prior. For 2026 premiums, that is the 2024 tax return. Annuity payments from a non-qualified contract include a taxable interest portion, and payments from a qualified annuity inside an IRA are fully taxable as ordinary income. Either way, most of that $1,580 shows up on the return. The same is true for required minimum distributions, taxable brokerage interest, and CD income. The Fed’s national average 12-month CD rate is 1.71% as of August 2026, and every dollar of that interest counts too.
That 4.68% yield on the 10‑year Treasury is the main reason annuity payout rates on fresh contracts are so appealing at the moment. But that favorable rate does nothing to alter how the IRS treats the income those annuities generate. The tax rules remain exactly the same regardless of how attractive the current yield environment happens to be.
What Comes Next
The 2027 Social Security cost-of-living adjustment is currently tracking at 3.1%, based on one of three Q3 months of CPI data. Core PCE is running at a 90.9th percentile reading relative to the last year, and headline CPI hit 332.8 in July 2026. Rising benefits and rising prices both push more retirees toward the same IRMAA cliffs.
Three things to consider before the next tax year closes. First, request a Form SSA-44 if a life-changing event (retirement, work stoppage, loss of a pension) reduces income; Medicare will recalculate IRMAA off current numbers instead of the two-year lookback. Second, coordinate Roth conversions and annuity start dates so large taxable events don’t stack in a single MAGI year. Third, watch the thresholds themselves. The $109,000 first-bracket line is a hard edge, and a few hundred dollars of extra reported income can cost thousands in higher premiums. The annuity is doing exactly what it promised. Medicare is doing exactly what its rules require. Planning around both is the retiree’s job.
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