The mechanics are narrower than the headlines suggest. This rule only touches the catch-up portion, the extra amount workers 50 and older can contribute above the standard deferral limit. For 2026, that's up to $8,000 (or up to $11,250 for those 60-63 using the SECURE 2.0 'super catch-up'). The base contribution, $24,500 for 2026, is unaffected and can still go in pre-tax if your plan allows it.

The income threshold looks at prior-year FICA wages from the specific employer sponsoring the plan, not household income or total compensation from all sources. A worker earning $160,000 in W-2 wages from their employer in 2025 is subject to the Roth requirement on their 2026 catch-up contributions, even if their spouse earns nothing and even if a large chunk of their own compensation is bonus or equity that doesn't show up the same way.

Employer plans have to accommodate this or lose the ability to offer catch-up contributions to anyone. A 401(k) plan without a Roth option available has two choices: add one, or stop allowing catch-up contributions altogether for participants above the wage threshold. Most large-plan providers have added Roth options in response; smaller plans may lag, which is worth confirming directly with your plan administrator rather than assuming.

The tax effect is straightforward but easy to miss in the moment. A pre-tax catch-up contribution reduces your current-year taxable income; a Roth catch-up contribution does not, you pay tax on that portion of your income now instead of deferring it. For someone in a high bracket during their final working years, that's real current-year tax cost, even though the money still grows tax-free and comes out tax-free in retirement.

The final regulations, issued jointly by Treasury and the IRS, gave plans a good-faith compliance window before full enforcement kicks in for taxable years beginning after December 31, 2026, while permitting earlier voluntary compliance. Practically, most large employer plans are already treating 2026 contributions as subject to the new rule.

If you're 50 or older, still working, and earned more than $150,000 in wages from your employer last year, check with HR or your plan administrator on how your catch-up contribution will be characterized for 2026 before you set your contribution elections for the year, not after your first paycheck of January already reflects it.

This doesn't change whether you should max out your catch-up contribution, it almost always still makes sense to. It changes the tax bill you pay to do it. Build the extra current-year tax into your withholding or estimated payments so it doesn't surprise you at filing time, and factor it into how you size any Roth conversions you're doing in the same year.

• Assuming this reduces your total allowed contribution. It doesn't, it only changes the tax treatment of the catch-up portion.
• Missing that the $150,000 threshold is based on wages from your specific employer, not household income.
• Not confirming your plan actually offers a Roth option before catch-up contributions start processing in January.
• Failing to account for the extra current-year taxable income once the catch-up contribution can no longer reduce it.