Overview

• Treasury and the IRS issued final regulations on September 16, 2025 confirming no further transition relief and requiring implementation of the Roth catch-up rule in 2026, with good-faith compliance permitted until formal effectiveness for taxable years beginning after December 31, 2026.
• The Roth requirement applies when a participant’s prior-year Box 3 FICA wages from the plan’s sponsoring employer exceed $145,000 (indexed), with limited aggregation allowed for common paymasters, controlled groups, and predecessor–successor arrangements.
• If a plan does not offer a Roth feature, participants subject to the requirement cannot make catch-up contributions, prompting design, notice, and systems updates for 2026, as legal advisers also warn of potential Section 409A issues for linked nonqualified plans.
• Plans may use a deemed Roth default if participants have an effective opportunity to elect otherwise; specified correction methods remain available, and no correction is needed for mistakes under $250 or certain late W-2 amendments.
• The separate “super” catch-up for ages 60–63 is confirmed for years after 2024, allowing the greater of $10,000 or 150% of the regular catch-up limit ($11,250 for 2025) in 401(k), 403(b), and governmental 457(b) plans.