By now most retirement savers know the headline: starting January 1, 2026, workers age 50 or older who earned more than $150,000 in prior-year FICA wages from their plan-sponsoring employer must direct any 401(k) catch-up contributions into a Roth (after-tax) account. What got less attention when the IRS and Treasury issued the final regulations on September 15, 2025, is a small but consequential operational provision: the deemed Roth election.
If your plan document contains it, your catch-up contributions can be automatically reclassified as Roth — without you filling out a single new form.
What the Deemed Roth Election Actually Does
Under the final regulations, a plan may include language stating that any participant subject to the Roth catch-up requirement is irrevocably deemed to have designated their catch-up contributions as Roth. To rely on the rule, plans must:
- Include the deemed-election language in the plan document.
- Treat the affected dollars as Roth contributions for tax purposes.
- Maintain the dollars in a separately tracked Roth subaccount.
For an affected high earner, the practical effect is that the $8,000 standard catch-up (or $11,250 super catch-up for ages 60–63) shifts from pre-tax to after-tax automatically once you cross the $24,500 base deferral limit — even if you never updated your contribution election.
Why This Matters in Real Paychecks
The change is invisible until you read the fine print, but it shows up in your paycheck math.
- Take-home pay drops. A pre-tax $8,000 catch-up at a 32% marginal federal rate would have reduced taxable income by roughly $2,560. Under a deemed Roth election, that deferral is gone.
- Withholding may need adjusting. If you set your W-4 last year assuming pre-tax catch-up contributions, you could be underwithheld for 2026.
- Roth tracking is now automatic. The plan, not the participant, decides the tax bucket. That is administratively cleaner but removes the worker's pre-tax option entirely.
What Counts Toward the $150,000 Threshold
The threshold is FICA wages, not adjusted gross income, not household income. Three implications:
- Self-employment income is excluded — it pays SECA, not FICA.
- Wages from a different employer don't count — the test is per-employer.
- A spouse's income is irrelevant, even on a joint return.
That means an entrepreneur earning $400,000 of self-employment income but $90,000 in W-2 wages from a side employer is not subject to the rule at that side employer.
Practical Steps Before Your Next Pay Period
- Pull your plan's summary plan description (SPD). Search for "deemed Roth election" or "automatic Roth designation."
- Confirm your 2025 FICA wages from box 3 of last year's W-2. Cross-check whether you tipped over $150,000 with one specific employer.
- Check if your plan offers Roth at all. Plans without a Roth feature are barred from accepting catch-ups from affected employees starting in 2026 — you could lose $8,000–$11,250 of contribution room entirely.
- Re-run your 2026 tax projection. If your catch-up just flipped from pre-tax to Roth, your taxable income is higher than your prior plan assumed.
- Watch the December 31, 2026 amendment deadline. Employers must adopt conforming amendments by year-end — that is when many workers will first see the deemed-election clause in writing.
The deemed Roth election is not a loophole or a penalty. It is plumbing — but it is plumbing that quietly changes the tax character of thousands of dollars of your retirement savings.
Sources: IRS Newsroom — Final Regulations on Roth Catch-Up Rule (September 16, 2025), Trucker Huss — The Roth Catch-Up Regulations Are Final, Groom Law Group — IRS Issues Final Regulations on Catch-Up Rule Changes, Benefits Law Advisor (Seyfarth Shaw), IRS Newsroom — 2026 Contribution Limits