IRS guidance says affected participants with more than $150,000 of prior-year wages from the plan sponsor generally must make 2026 catch-up contributions as Roth contributions when the plan offers Roth catch-up.
2026 change
Prior-year plan-sponsor wages drive the Roth requirement
The IRS says a participant in a plan with a Roth feature who had prior-year wages from the plan sponsor above $150,000 generally must make catch-up contributions as Roth in 2026. Household income and Taiwan income are not the stated wage test.
TSMC Arizona employees should confirm which W-2 wage amount and employer entity the plan uses, especially after a transfer from another affiliate or a partial U.S. year.
Contribution limits
Regular deferrals and catch-up amounts remain separate
The 2026 basic employee elective-deferral limit is $24,500. The standard catch-up is $8,000 for eligible participants age 50 or older, while participants turning 60 through 63 can have an $11,250 catch-up if the plan permits.
Current TSMC Arizona plan materials determine whether catch-up and Roth features are offered and how payroll implements them.
Payroll checklist
Verify age, wages and year-to-date contributions
Confirm date of birth, prior-year TSMC Arizona wages, current contribution sources and any contributions made to another employer plan during the year.
Do not infer the Arizona match from a forum or another employee group. The Roth catch-up rule and employer match are different plan questions.
Frequently asked questions
Questions employees ask next
What is the Roth catch-up wage threshold for 2026?
$150,000 of prior-year wages from the plan sponsor under current IRS guidance.
What is the 2026 catch-up limit?
$8,000 for most eligible participants age 50 or older and $11,250 for participants turning 60 through 63, if the plan permits.
Does this rule confirm the TSMC Arizona 401(k) match?
No. Catch-up tax treatment and the employer contribution formula are separate. Verify the match in current Arizona documents.
Primary sources
What this guide is based on
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