Who Pays the Medicare Part B Premium for Dual Eligible Beneficiaries

Your parent just got approved for Medicaid alongside their existing Medicare. They're dual eligible now — but the $202.90 Part B premium is still coming out of their Social Security check. Who's supposed to be paying that?

The Short Answer

For dual eligible beneficiaries enrolled in QMB, SLMB, or QI, the state Medicaid agency pays the Part B premium. The mechanism is the "premium buy-in" — the state instructs CMS to take over the premium payment, and SSA stops deducting it from your parent's monthly Social Security benefit.

For full dual eligibles who qualify for full Medicaid (not just an MSP), the state also pays the Part B premium as part of comprehensive Medicaid coverage.

Either way, your parent's Social Security check should eventually increase by $202.90/month once the buy-in processes.

Why the Deduction Doesn't Stop Immediately

The buy-in requires a data exchange between the state Medicaid agency, CMS, and SSA. After the state records the buy-in flag in its MMIS system, the record travels through the COBA system to CMS, which reconciles it and then instructs SSA to stop the deduction.

This chain typically takes 60 to 90 days. During the entire gap, SSA continues withholding the premium as if nothing changed. This is normal — not an error.

The premiums withheld during the gap are refunded retroactively once the buy-in activates. SSA issues the refund as a lump-sum payment through the same channel your parent receives their monthly benefit.

What About Part A Premiums?

Most Medicare beneficiaries get Part A premium-free based on their work history (or their spouse's). If your parent must pay a Part A premium — up to $565/month in 2026 — QMB covers that too.

QDWI specifically exists for working disabled individuals under 65 who lost premium-free Part A. The state pays their Part A premium, which can run up to $565/month.

SLMB and QI cover the Part B premium only — not Part A.

What Dual Eligibles Don't Pay

Under QMB with full dual eligibility, your parent's out-of-pocket Medicare costs are effectively zero:

• Part B premium — paid by the state
• Part A premium (if applicable) — paid by the state
• Part A deductible ($1,736 per benefit period) — covered
• Part B deductible ($283/year) — covered
• Part B coinsurance (the uncapped 20%) — covered
• Part D copays — reduced to $5.10 generic / $12.65 brand-name through automatic Extra Help enrollment

Providers cannot balance bill QMB beneficiaries for any remaining amount. If a doctor or hospital sends your parent a bill for deductibles or coinsurance, that bill is illegal under Section 1902(n)(3)(B) of the Social Security Act.

Keep Paying Until the Buy-In Activates

Do not contact SSA to stop the premium deduction based on the state approval letter alone. If the deduction stops before the buy-in is officially active in SSA's system, Medicare can terminate your parent's Part B coverage. Reinstatement may require waiting for the next General Enrollment Period (January 1–March 31), with coverage beginning the month after enrollment.

The withholding gap is temporary. The refund is guaranteed. Treat it as a short-term float.

If the buy-in hasn't processed after 90 days, call the state Medicaid agency to confirm the COBA transaction date, then call SSA to verify they've received the flag. Document every call.

The Medicare Savings Programs toolkit walks through the full buy-in timeline and includes the application tracker for monitoring the processing status across all three agencies.

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