Is The Medicare Part B Premium A Percentage Of Our Social Security Amount?

Full analysis

A short explainer from AMAC Foundation advisor Rusty answering a single listener question: Medicare Part B premiums are not a percentage of your Social Security benefit. The episode walks through how the standard premium is set, who pays less (hold-harmless provision), and who pays more (IRMAA). Thin on depth, but the mechanics are explained correctly.

What was covered

• How CMS sets the Part B premium. Each October, the Centers for Medicare & Medicaid Services (CMS) estimates total Part B program costs for the coming year, then prices enrollee premiums to cover roughly 25% of that total. The federal government covers the rest.
• The 2026 standard Part B premium. Rusty states the standard monthly amount is $202.90 for 2026. The 2027 figure will be announced in October 2026.
• The hold-harmless provision. If the annual Social Security COLA (cost-of-living adjustment) is too small to absorb a Part B premium increase, a beneficiary's Part B premium is reduced so their net Social Security check cannot fall. Rusty notes there are exceptions.
• IRMAA — the Income-Related Monthly Adjustment Amount. Higher-income Medicare enrollees pay a surcharge on top of the standard premium, on a sliding scale. At the highest income tier, the Part B premium can reach $690 per month.
• The two-year income lookback. IRS determines IRMAA liability using tax returns from two years prior. When October arrives and next year's premium is set, the most recent complete tax year available is two years back — so 2026 IRMAA is based on 2024 income.
• IRMAA applies to Part D as well. Higher-income enrollees who owe an IRMAA surcharge on Part B also pay a higher premium on their Medicare Part D (prescription drug) coverage.

Notable claims & predictions

• Rusty states that Medicare Part B enrollee premiums are designed to offset "about 25% of CMS's anticipated total Medicare Part B cost," with the federal government covering the remaining 75%.
• Rusty says the standard 2026 Part B premium is $202.90 per month — up from prior years, though no prior-year figure is given for comparison.
• Rusty says the maximum Part B premium for the highest-income tier reaches $690 per month for 2026.
• Rusty says the hold-harmless rule means "the monthly Social Security benefit cannot decrease as a result of a Medicare Premium increase" — but cautions there are exceptions to this protection.
• Rusty notes income from two years prior is always used to assess IRMAA, because the IRS has not yet processed the current year's returns when October premium-setting occurs.

Fact check

• "Standard Part B premium is $202.90 for 2026." This matches CMS's published 2026 figure. No issue.
• "25% of total Part B costs is borne by enrollee premiums." This is the statutory formula established by federal law and is accurate as a general rule. The actual percentage can shift slightly depending on program costs and enrollee counts, but the 25% target is the correct statutory benchmark.
• "IRMAA applies to both Part B and Part D." Correct. Both coverages carry income-related surcharges.
• "The two-year lookback." Accurate. SSA and CMS use the most recently available tax year, which is two years prior when premiums are set in the fall.
• "Maximum Part B premium can reach $690/month." The transcript states this figure for 2026's top IRMAA tier. This is consistent with CMS published tables for 2026. No issue.
• Hold-harmless exceptions. Rusty correctly flags that exceptions exist (new Medicare enrollees, those enrolled in Medicaid, those paying premiums directly rather than through Social Security withholding are among those not protected), though he does not enumerate them. That omission is worth noting — if you are not yet collecting Social Security while enrolled in Part B, hold-harmless does not protect you.

No claims that fail scrutiny. The one meaningful gap is that Rusty does not name which enrollees fall outside hold-harmless protection, which could matter to listeners who are Medicare-eligible but haven't yet claimed Social Security.

Why this matters for you

• If your income two years ago crossed an IRMAA threshold, you may be paying more than $202.90/month for Part B right now — and more for Part D as well. If your income has since dropped significantly (retirement, a one-time event like a Roth conversion), you can file Form SSA-44 with Social Security to request a reduction based on current income. The episode doesn't mention this appeal option, but the two-year lookback rule Rusty describes is exactly why it exists.
• If you haven't yet claimed Social Security but are enrolled in Medicare, the hold-harmless rule does not apply to you. You pay the full standard premium (or higher, if IRMAA applies), and a premium increase won't be cushioned by any COLA calculation. Worth knowing before you plan your claiming age.
• The 2027 premium — whatever it turns out to be — will be announced this October. If you're doing retirement income planning for next year, that announcement is worth tracking. A meaningful premium jump could affect your monthly cash flow if you rely on Social Security net of Part B withholding.
• Otherwise, this is a foundational explainer, not a call to action. If you already understand how Part B premiums are set, IRMAA exists, and the two-year lookback works, there is little new here this week.