Workers who earned more than $150,000 from their employer in the prior year will no longer be able to stash catch-up 401(k) contributions in a traditional pre-tax account. Beginning in 2026, those participants must direct catch-up dollars into a Roth account if their plan offers the feature, paying income tax on the money before it goes in. Treasury and the IRS finalized the rules under IR-2025-91, putting a firm deadline on a change that Congress authorized through the SECURE 2.0 Act but twice delayed.
How the $150,000 Roth catch-up rule changes retirement math
The rule targets a specific slice of retirement savers: those aged 50 and older who make extra contributions above the standard 401(k) limit. Under current practice, most plans let participants choose whether catch-up dollars go pre-tax or Roth. Starting in 2026, that choice disappears for higher earners. Anyone whose prior-year FICA wages from the plan sponsor topped $150,000 must use a Roth designation for every catch-up dollar.
The practical effect is straightforward: affected savers lose the upfront tax deduction on catch-up contributions. In return, money in a Roth account grows tax-free and comes out tax-free in retirement. For someone in peak earning years who expects a lower tax bracket after leaving the workforce, the forced Roth treatment could mean paying more in taxes overall. For someone who expects taxes to stay flat or rise, the Roth path may prove beneficial. The rule removes the ability to weigh those scenarios and choose.
One detail worth tracking is the wage threshold itself. The statutory figure is $145,000, indexed for inflation, according to the codified regulation at 26 CFR 1.414(v)-2. For the 2026 plan year, the IRS has set the operational number at $150,000. The gap reflects inflation adjustments, and the threshold will continue to move in future years. Wages for this test are defined as FICA wages under Internal Revenue Code section 3121(a), which means they include salary, bonuses, and most taxable compensation but exclude certain fringe benefits.
Another subtlety is that the test looks only at wages from the employer sponsoring the plan. A worker with multiple jobs could exceed $150,000 in total income but still fall below the line for a particular plan if their FICA wages from that sponsor are lower. Conversely, a worker who switches employers midyear may need to watch how each plan applies the rule based on its own wage history. The final regulations clarify that plan administrators may generally rely on the sponsor’s payroll data rather than aggregating across unrelated employers.
What Treasury’s final regulations actually require of plan sponsors
The final regulations go well beyond a simple income test. They address correction procedures for plans that accidentally route a high earner’s catch-up into a pre-tax bucket, spell out deemed Roth election mechanics, and cover wage aggregation rules for workers in multiemployer arrangements. Plans covering employees in Puerto Rico also received specific guidance on how to apply the catch-up limitations alongside local tax rules.
For plan sponsors, the operational burden is real. Payroll and recordkeeping systems must identify which participants crossed the wage line in the prior year and then automatically redirect their catch-up elections into a Roth sub-account. Plans that do not currently offer a Roth feature face a harder choice: add one or stop offering catch-up contributions to higher earners entirely. The IRS has made clear that a plan cannot keep pre-tax catch-up contributions for affected participants once the new rules take effect.
The regulations also outline how plans should communicate these changes. Sponsors are expected to update summary plan descriptions, enrollment materials, and online interfaces so that participants understand when and why their catch-up dollars are being treated as Roth. If a participant fails to make an explicit Roth election but is over the wage threshold, the plan can treat their existing catch-up deferral instructions as a deemed Roth election, provided notices are clear and timely.
Errors are inevitable when complex rules meet real-world payroll systems, so Treasury devoted space to correction relief. If a plan mistakenly accepts pre-tax catch-up contributions from a participant who should have been Roth-only, the final regulations allow for reclassification or distribution corrections within specified time frames. This approach is designed to avoid disqualifying an entire plan because of isolated administrative mistakes, as long as sponsors act promptly once they discover the problem.
Multiemployer and multiple-employer plans face additional wrinkles. The rules describe when wages from different contributing employers must be aggregated to determine whether a participant crosses the $150,000 line. Administrators in these arrangements may need more robust data-sharing with participating employers to apply the test accurately and avoid inconsistent treatment of the same worker across related plans.
Key dates, transition relief, and what comes next
The government’s implementation timeline is set out in the final regulations and related guidance, including Internal Revenue Bulletin materials that consolidate SECURE 2.0 interpretations. The Roth-only catch-up rule applies to plan years beginning on or after January 1, 2026, giving sponsors one more year to adapt systems and update plan features. Earlier enforcement dates were postponed to avoid disruption when many employers were still grappling with other SECURE 2.0 changes.
Between now and the effective date, plan sponsors, recordkeepers, and payroll providers will be focused on testing data feeds, refining eligibility logic, and drafting participant communications. Higher-earning workers age 50 and older may want to revisit their retirement projections, since losing the pre-tax catch-up option could change both their current tax bill and their after-tax income in retirement. Financial planners are likely to emphasize coordination among 401(k) contributions, IRAs, and taxable accounts to restore some of the flexibility that the new rule takes away.
Once the Roth-only requirement is in place, Congress could still revisit the policy, but for now Treasury and the IRS have locked in the framework. For affected savers, the choice is no longer whether to use Roth for catch-up contributions, but how to integrate that mandatory Roth layer into a broader retirement strategy that balances tax diversification, cash-flow needs, and long-term estate planning goals.
