The ACA subsidy cliff, 2026 edition

For three years, the rule was a gentle slope: marketplace premium subsidies phased out gradually, and nobody's tax return blew up over one extra dollar of income. That era is over. With the enhanced credits expired, 2026 restored the original structure — and with it the infamous 400% cliff: cross 400% of the federal poverty level by a single dollar and you don't lose a little subsidy, you lose all of it.

If you're retired or semi-retired and buying your own coverage before Medicare at 65, this is now one of the highest effective marginal tax rates in the entire code, and it's hiding in your health insurance.

How the cliff works

Marketplace subsidies key off MAGI — modified adjusted gross income — measured against the federal poverty level for your household size. Below 400% FPL, your required premium contribution is capped at a percentage of income, and the subsidy covers the rest of the benchmark plan. At 400.0001%? The cap disappears entirely, and you pay the full sticker price.

The dollar stakes are not subtle. For a 60-something couple, unsubsidized benchmark premiums commonly run $1,500–2,500/month. A couple just under the line might pay a few hundred dollars a month; the same couple one dollar over pays all of it. That single dollar of income can cost $10,000–20,000 in lost credits for the year. There is no other place in the tax code where $1 of income costs five figures.

The cruel part for early retirees: this is mostly a voluntary number. Wage earners can't easily control MAGI. Retirees — living off cash, basis, Roth dollars, and chosen realizations — usually can.

What counts toward MAGI (and what doesn't)

Counts: traditional IRA/401(k) withdrawals, Roth conversions, capital gains (including the ones a mutual fund distributes to you in December whether you asked or not), dividends, interest, and — easy to forget — Social Security benefits, including the portion that isn't federally taxable.

Doesn't count: Roth withdrawals (qualified), return of basis from a taxable account, cash savings, HSA withdrawals for medical costs, and loan proceeds.

That asymmetry is the whole playbook. Two retirees can fund identical $80,000 lifestyles — one realizing $85,000 of MAGI and zero subsidy, the other realizing $48,000 (part basis, part Roth, part gains) and collecting five figures of premium credits, every year until Medicare.

The playbook, in priority order

1. Know your line. Compute 400% FPL for your household size for the plan year, then set your personal ceiling 5–10% below it — December capital-gain distributions and interest income have a habit of arriving uninvited.
2. Sequence the gap years. The years between retirement and 65 are precious low-bracket years, which makes them tempting for Roth conversions — but every converted dollar is MAGI. The genuinely hard tradeoff at this stage is conversions versus subsidies, and the answer depends on your bracket later (RMDs at 75) versus the credit now. This is exactly the modeling our Roth conversion calculator and the full app are built for.
3. Spend the "free" money first in cliff years. Cash, basis, and existing Roth contributions fund spending without touching MAGI.
4. Watch the December torpedo. Mutual funds in taxable accounts distribute gains in Q4. If you're skating near the line, know your funds' estimated distributions by November — or hold ETFs, which mostly don't do this.
5. If you're going over anyway, go way over. The worst outcome is exceeding the line by $5,000. If a big realization is unavoidable, bunch it: blow far past the cliff in one year (subsidy was lost anyway), then run lean and subsidized the next.

Run your own numbers — household size, income, age — on the ACA subsidy calculator to see your premium credit and exactly how much MAGI headroom you have. If you're modeling a retirement that starts before 65, the retire at 60 page covers how the bridge years fit the bigger plan, and Granary models the whole thing — subsidies, conversions, brackets, and RMDs — against your actual accounts.

This is planning education, not tax advice; FPL tables and marketplace rules vary by state and year, so verify your specific numbers before acting.