The math of the window
If you turn 60, 61, 62, or 63 at any point during 2026, your catch-up limit rises from $8,000 to $11,250 on top of the base $24,500. That's $35,750 of elective deferral for the year, on a 401(k), 403(b), 457(b), or TSP.
Why it exists
SECURE 2.0 was designed to shore up late-career savings for people who got hit by pension freezes, caregiving gaps, or the 2008 and 2020 recessions. The drafters picked a four-year window because the average last working years before retirement concentrate in that range.
Why missing it is costly
Three reasons. First, you cannot carry unused capacity forward — each year's limit resets. Second, a dollar saved at 62 still gets five to seven years of tax-free or tax-deferred growth before a typical retirement draw begins, which is about 40% extra at a 7% real return. Third, late-career earnings are usually the highest of your career, meaning the marginal tax rate you're sheltering is the biggest marginal rate of your life.
How to capture it
Increase your deferral percentage in December 2025 or January 2026. On a $150,000 salary, going from 16% to 24% gets you to $35,750. HR systems sometimes cap deferrals at a visible percentage; if so, file a manual request to exceed the default cap.
What if you're over 63?
You drop back to the regular $8,000 catch-up. So the strategy at 64+ is to shift attention to the IRA catch-up ($1,100 extra), HSA catch-up ($1,000 extra), and any 457(b) stacking if you work for a state or federal employer.