SECURE 2.0 Act Rules to Reshape High-Income Retirement Savings Starting in 2026

WASHINGTON — A set of significant changes to 401(k) plan rules, enacted as part of the SECURE 2.0 Act, are set to take effect on January 1, 2026, creating new retirement savings avenues for high-income earners while imposing new requirements on employers. The new regulations will allow for substantially larger after-tax contributions that can be converted to Roth accounts and will mandate that catch-up contributions for high earners be made on a Roth basis.

The changes center on the Internal Revenue Code's Section 415(c), which governs the total annual contributions to a 401(k) from all sources. For 2026, this overall limit is set at $72,000. With the standard employee elective deferral limit at $24,500, a considerable gap is created. This space can be filled with a combination of employer matching funds and employee after-tax contributions, which can then be converted to a Roth 401(k) or Roth IRA, allowing for tax-free growth and withdrawals in retirement.

For business owners and key executives, these rule changes represent a significant, if complex, strategic opportunity. In our experience, many successful entrepreneurs and professionals find themselves phased out of direct Roth IRA contributions due to income limits, yet they are precisely the people who benefit most from tax diversification in retirement. The expansion of the after-tax 401(k) strategy is not a loophole; it is a powerful planning tool that allows them to build a substantial tax-free nest egg. However, capitalizing on this requires careful navigation of both personal contribution strategies and corporate plan compliance. We see many mid-sized companies that are not yet prepared for the mandatory Roth catch-up provision for their high-earning employees, which could create administrative headaches and employee dissatisfaction if not handled proactively. Proper tax preparation and compliance is essential to ensure the company’s retirement plan is properly amended and administered. To assess how these changes affect your personal retirement strategy and your company's obligations, contact C&S Finance Group LLC at csfinancegroup.com for guidance.

The mechanism, often referred to as a “mega backdoor Roth” strategy, allows high earners who are otherwise ineligible for direct Roth IRA contributions to build significant tax-free retirement assets. For 2026, the income phase-out for direct Roth IRA contributions begins at a modified adjusted gross income (MAGI) of $153,000 for single filers and $242,000 for those married filing jointly, according to figures from Vanguard and Charles Schwab. The 401(k) after-tax strategy has no such income restrictions.

For an employee who contributes the maximum $24,500 to their 401(k) and receives a hypothetical employer match, the remaining difference up to the $72,000 overall limit can be contributed on an after-tax basis. For example, if an employer contributes $11,750, the employee could contribute an additional $36,250 in after-tax dollars, according to an analysis based on the 2026 limits. These after-tax contributions can then be converted to a Roth account, where all future earnings grow tax-free.

Further expanding the savings potential are new catch-up contribution rules. Beginning in 2026, employees aged 50 and over can contribute an additional $8,000. A new provision, the “Super Catch-Up,” allows those aged 60 to 63 to contribute an even greater amount, set at $11,250 for 2026. For an employee in this age bracket, the total potential contribution capacity rises to $83,250 for the year.

A critical component of the SECURE 2.0 Act changes directly impacts employers. Starting January 1, 2026, any employee with prior-year Social Security wages exceeding $145,000 must make their catch-up contributions exclusively as Roth (after-tax) contributions. This threshold will be indexed for inflation in subsequent years. This mandate means that if a company’s 401(k) plan does not currently include a Roth contribution feature, it must be amended to add one.

According to guidance from law firm Baker Donelson, employers who wish to continue allowing their high-earning employees to make catch-up contributions must amend their plans to permit Roth contributions by the end of the 2026 plan year. However, the decision and coordination with plan recordkeepers should happen well before the January 1, 2026, effective date to ensure a smooth transition. The alternative for employers is to suspend catch-up contributions entirely for this group of employees, a move that would likely be unpopular with senior staff and executives.

As the 2026 deadline approaches, business owners and plan administrators will need to review their current retirement plan documents and consult with their advisors. The focus will be on implementing necessary plan amendments and communicating the new options and requirements to employees, ensuring that both the company and its key personnel can fully leverage the updated retirement saving landscape.