Mandatory Roth Catch-Up 2026 — Does This Affect My Solo 401k?

[Jack Z]

I’m 55 and operate an S-Corp. My W-2 from the business is around $180,000. I heard there are new mandatory Roth catch-up rules starting in 2026 that could affect how I make catch-up contributions to my Solo 401k. What exactly are these rules, and how do they impact me specifically?

Jack Z

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[Mark Nolan]

Yes — the new mandatory Roth catch-up contribution rules, which took effect January 1, 2026 under the Secure Act, directly affect your situation. Based on what you’ve described — an S-Corp with W-2 wages of $180,000 — you are subject to these new requirements.

Explanation of the rule: if you operate your self-employed business as an S-Corp or C-Corp, and your W-2 Box 3 (Social Security wages) from that business exceed $145,000 (this amount changes each year based on the inflation index), then any catch-up contribution you make to your Solo 401k must be treated as a Roth Solo 401k contribution — it can no longer be made as a pre-tax employee deferral.

For your situation specifically:

• Your W-2 Box 3 wages of $180,000 exceed the $145,000 threshold
• At age 57, you qualify for the standard $8,000 catch-up contribution (ages 50–59 and 64+)
• Under the mandatory Roth catch-up rule, that $8,000 must now be contributed as a Roth Solo 401k employee deferral — not as a pre-tax contribution
• You will pay income tax on that $8,000 in the year it is contributed — no pre-tax deduction is available for it
• At retirement (age 59½+, after the five-year holding period), that $8,000 and its earnings are distributed completely tax-free

Important Clarification: The mandatory Roth catch-up rule applies only to S-Corps and C-Corps. It does not apply to sole proprietorships, partnerships, or Schedule F filers (farmers). If your self-employed business is structured as a sole proprietorship or partnership, you may still make catch-up contributions on a pre-tax basis regardless of your income level.

Visit the following to learn more: https://www.mysolo401k.net/mandatory-roth-catch-up-contributions-including-401k-solo-401k-effective-january-1-2026/

mysolo401k.net

Mandatory Roth Catch-Up Contributions (Including 401k & Solo 401k ) Effective January 1, 2026 - My Solo 401k Financial

My Solo 401k Financial offers self-directed Solo 401k, IRA LLC & ROBS 401K Retirement Plans. Learn about Mandatory Roth Catch-Up Contributions (Including 401k & Solo 401k ) Effective January 1, 2026

Mark Nolan

Compliance Officer

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1-800-489-7571 www.mysolo401k.net

[Eric N]

Oh wow, learned something new today (that the SECURE 2.0 catch-up contribution rule doesn’t apply to sole proprietors/independent contractors).

I think I’ll still continue making mine as Roth just to have the tax advantage when I retire.

Eric N

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