Roth Conversions and ACA Subsidies: The 2026 Premium Tax Credit Cliff

You've retired early — 57, 60, 63 — and you're on an ACA Marketplace health plan waiting for Medicare. You know the golden window is open: no earned income, no RMDs yet, the best tax brackets of your adult life. It seems like the ideal time to convert traditional IRA money to Roth.

There's a second tax system you need to plan around. Your ACA premium tax credits are calculated on income. Roth conversions are income. And in 2026, the income cliff is back: once your Modified Adjusted Gross Income crosses 400% of the federal poverty level — approximately $62,600 for a single person, $84,600 for a two-person household — every dollar of advance premium tax credit you received during the year must be repaid at tax time. All of it.¹²

The OBBBA, signed in July 2025, made this worse: it eliminated the repayment caps that previously softened the penalty for inadvertently crossing the line. There is no ceiling on how much you owe back.³

How ACA subsidies count Roth conversion income

The ACA uses Modified Adjusted Gross Income (MAGI) to calculate premium tax credit eligibility. For Marketplace purposes, MAGI is your regular AGI with a handful of deductions added back. Roth conversion income counts in full.

When you convert $50,000 from a traditional IRA to Roth, that $50,000 shows up on Form 1040 line 4b as a taxable IRA distribution. It flows into your AGI, then your MAGI. There's no exception for retirement distributions or pre-tax contributions — the ACA sees the full conversion amount as income for the year.

Other income items that count toward ACA MAGI:

• Taxable Social Security benefits (up to 85% of SS, depending on combined income)
• Capital gains — including long-term gains on stocks, funds, real estate
• Dividends (qualified and ordinary)
• Interest income
• Part-time or freelance earned income
• Rental income (net of expenses)
• Traditional IRA distributions, including RMDs once they begin at 73+

Notably, Roth distributions do not count — withdrawals from already-converted Roth accounts are tax-free and excluded from MAGI entirely. This is part of the long-term advantage of completing conversions before ACA years end: money already in Roth won't erode future ACA eligibility.

The 2026 cliff: what changed and why it matters now

From 2021 through 2025, the American Rescue Plan Act and Inflation Reduction Act temporarily enhanced ACA subsidies. The "hard cliff" at 400% FPL was softened: anyone paying more than 8.5% of income toward premiums could receive a credit, regardless of how far above 400% FPL they were.

That enhancement expired after 2025. Starting with 2026 coverage, the original ACA rules are back: income above 400% FPL means zero premium tax credit. The Inflation Reduction Act extension was not renewed.²

For 2026 Marketplace coverage, the 400% FPL thresholds (based on 2025 HHS poverty guidelines) are:⁴

Alaska and Hawaii use higher FPL guidelines. Thresholds apply to 48 contiguous states + D.C. Verify current-year thresholds at healthcare.gov.

What crossing the cliff actually costs

A 60-year-old enrolled in an ACA Marketplace silver plan can pay $1,100–$2,000/month in unsubsidized premiums depending on location. Advance premium tax credits reduce that to what the ACA considers "affordable" at a given income level — a subsidy of $400–$1,200/month is common for early retirees in the 200–350% FPL range.

Consider this scenario:

The cliff is not a gradual phase-out. Federal income tax brackets work incrementally — every dollar in a bracket is taxed at that bracket's rate. The ACA cliff does not. Cross it by a dollar and you lose the entire year's subsidy.

Calculating your ACA conversion ceiling

The ACA conversion ceiling is the maximum Roth conversion you can execute while keeping MAGI under the 400% FPL threshold for your household. It's a straightforward subtraction:

ACA conversion ceiling =
  400% FPL for your household size
  − taxable Social Security income
  − capital gains and dividends
  − interest income
  − rental or business income
  − part-time earned income
  = Maximum Roth conversion before cliff

Worked example — couple, household of 2: He receives $22,000/year in Social Security ($18,700 taxable at 85%). She has $7,000 in dividends and capital gains. Combined non-conversion income: $25,700. Their 400% FPL ceiling: $84,600. Conversion ceiling: $84,600 − $25,700 = $58,900.

Convert $58,000 and they're $600 under the ceiling — full subsidy eligibility intact. Convert $59,000 and they've crossed it — all advance credits are repaid.

A few things that reduce your ceiling more than people expect:

• Capital gains in the year of a home sale. Even a home sale that's mostly shielded by the $500K MFJ primary-residence exclusion may produce gains above the exclusion — and those gains count.
• Year-end mutual fund distributions. Capital gain distributions from funds held in taxable accounts are included in MAGI. These often arrive in November–December, after you've already committed to a conversion amount.
• Spousal income changes. If a spouse takes temporary work, MAGI rises. Real-time tracking matters.

The three-phase conversion calendar: COBRA → ACA → Medicare

Most early retirees pass through three health coverage phases between retirement and Medicare, each with different conversion constraints:

Phase 1 — COBRA (typically 0–18 months post-retirement)

COBRA extends your prior employer coverage at your own expense. It is not income-linked — there's no ACA subsidy and therefore no ACA income ceiling. This is often the best window for large initial conversions: no ACA constraint, income typically drops to its lowest level in the year you retire (especially mid-year retirees with a partial working income), and you can convert aggressively before the ACA calculus begins. Many advisors structure a deliberate "COBRA sprint" — front-loading conversions in the first 12–18 months of retirement.

Phase 2 — ACA Marketplace (typically age 55–65)

Once on a Marketplace plan, your annual conversion ceiling applies. Strategy shifts to filling tax brackets without crossing the 400% FPL line. A couple with a $58,000 ceiling converting each year for 8 years can move $464,000 out of a traditional IRA — meaningful progress on a large balance — while retaining full subsidy eligibility throughout.

Phase 3 — Medicare (age 65+)

The ACA constraint disappears when you enroll in Medicare. But IRMAA replaces it: Medicare surcharges based on income two years prior. The good news: IRMAA thresholds are substantially higher than the ACA ceiling. For a married couple, the first IRMAA tier doesn't trigger until $218,000 in MAGI — more than 2× the ACA ceiling. The Medicare years typically allow considerably larger conversions. See the IRMAA strategy guide for full tier tables and cliff math.

The ACA-to-Medicare transition year

The year you turn 65 and enroll in Medicare requires specific planning. Your IRMAA for the first Medicare year is based on income from two years prior — meaning aggressive ACA-year conversions can cascade into elevated first-year Medicare premiums.

If you're converting up to the $84,600 ceiling during ACA years, your MAGI is safely below the $218,000 MFJ IRMAA threshold — no conflict. But if you deliberately cross the ACA cliff in your final Marketplace year (doing a large conversion and absorbing the subsidy loss), remember that MAGI flows forward into the IRMAA lookback. A $200,000 conversion in your last ACA year would affect Medicare premiums two years later.

The IRMAA guide covers how to model this bridge year, including the SSA-44 appeal process for retirees whose income dropped significantly.

When it makes sense to cross the cliff anyway

The ACA cliff is a real cost — but not an automatic veto on larger conversions. Three situations where crossing the ceiling can still be the right financial decision:

• The lifetime math is clearly positive. If your traditional IRA is large enough that RMDs will push income into 32–37% brackets, the lifetime tax savings from converting at 22–24% may outweigh several years of lost ACA credits. A lifetime NPV analysis that incorporates subsidy loss will quantify whether the tradeoff is positive. Use the lifetime NPV calculator as a starting point.
• Your subsidies are modest relative to conversion savings. In high-premium states, subsidies can be smaller than they appear (the ACA's 400% FPL threshold is the same everywhere, but premiums vary widely by state). If you're only receiving $2,000–4,000/year in credits and the conversion's tax savings are $7,000+, crossing the cliff deliberately can be the right call.
• You're in your last ACA years before Medicare. Some advisors plan a final-year conversion spike — accepting one year's subsidy loss for a large conversion that meaningfully reduces the IRA balance before Medicare rules take over. The math works when the single-year subsidy loss is smaller than the long-run tax savings from the larger Roth balance.

Frequently asked questions

Does a Roth conversion count as income for ACA subsidies?

Yes. Roth conversions are taxable IRA distributions that appear in your AGI and ACA MAGI in full. Every dollar converted adds a dollar to your Marketplace income calculation — the same as earned income or a pension payment.

What if I accidentally go $1,000 over the cliff?

Post-OBBBA, you owe back the full advance premium tax credit on Form 8962 — no repayment cap. If you received $10,000 in advance credits during the year and your final MAGI is $1,000 above 400% FPL, you repay all $10,000. The only reliable fix is avoiding it — which means real-time MAGI tracking through the year, especially in November–December when mutual fund distributions and year-end decisions arrive. Advisors who specialize in this run MAGI estimates quarterly and finalize conversion amounts before year-end.

Can I do smaller, annual conversions to stay under the ceiling?

Yes — and that's the standard strategy. Partial conversions sized to your ceiling allow meaningful progress each year while preserving subsidy eligibility. A couple with a $58,000 ceiling converting for 8–10 ACA years can move $460,000–$580,000 out of a large IRA before Medicare begins — then continue at higher amounts once on Medicare where IRMAA thresholds allow more room.

Does delaying Social Security increase my conversion ceiling?

Yes, significantly. Social Security income reduces your conversion ceiling dollar-for-dollar (85% of SS is typically included in ACA MAGI when combined income is high). Retirees who delay SS until 70 often have $15,000–$22,000 more annual conversion room during ACA years compared to those who claim at 62. This is one reason delaying SS pairs well with an early retirement Roth conversion strategy. See the Roth conversion and Social Security guide for the full interaction analysis.

My spouse still works. Does their income affect our ACA ceiling?

If you file jointly, the household MAGI includes both spouses' income. A working spouse's salary reduces — or eliminates — the conversion ceiling. In this case, the Roth conversion strategy may need to wait until both spouses are no longer employed, or the converting spouse may file separately (though married filing separately has significant drawbacks, including ineligibility for premium tax credits entirely for most filers).

What happens to existing Roth accounts during ACA years? Do they affect income?

No. Qualified Roth distributions are excluded from AGI and ACA MAGI entirely. Withdrawals from Roth accounts you've held for 5+ years and accessed after 59½ are tax-free and invisible to the ACA. This is a core advantage of converting earlier: once money is in Roth, it never competes with your ACA ceiling again.

The multi-year planning picture

Managing ACA subsidies and Roth conversions across 8–10 Marketplace years — with COBRA before and Medicare after — is exactly the kind of multi-year optimization where a specialist advisor adds the most value. The moving pieces:

• Real-time MAGI tracking to avoid inadvertent ceiling crossings (fund distributions arrive unpredictably)
• COBRA sprint planning in the first year of retirement
• Annual conversion amount calibration before December 31
• Coordinating Social Security delay to preserve conversion room
• Deciding in which years it's worth crossing the ACA cliff — and by how much
• Bridging from ACA ceilings to IRMAA thresholds as Medicare approaches

Use the lifetime NPV calculator to model the broad conversion scenario, and the tax bracket calculator to see how much bracket room you have in a given year. For the full multi-year plan — including ACA ceiling management — connect with a specialist advisor.

Sources

1. IRS: Eligibility for the Premium Tax Credit — income requirements, 400% FPL rule, and Form 8962 repayment provisions for excess advance credits.
2. Kitces: Reducing ACA Health Insurance Premiums After Enhanced PTC Expiration — analysis of the return of the hard 400% FPL cliff in 2026 after expiration of ARP/IRA enhancements; premium cost impact.
3. Get IRS Help: OBBBA ACA Subsidy and Premium Tax Credit Clawback — OBBBA eliminated advance credit repayment caps starting with 2026 coverage; full clawback applies.
4. Hummingbird Insurance: 2026 ACA Income Limits for Tax Credit Subsidies — 400% FPL thresholds for 2026 coverage based on 2025 HHS poverty guidelines: $62,600 single, $84,600 two-person household.

FPL thresholds based on 2025 HHS Poverty Guidelines used for 2026 ACA Marketplace coverage. OBBBA changes to repayment caps apply to 2026 coverage year. All values verified May 2026. State-specific premium amounts vary; verify subsidy eligibility at healthcare.gov for your state and plan.