The Overemployed 401(k) Trap: How Two Employer Plans Blow Past the Deferral Limit and Get Your Money Taxed Twice.

A platform engineer is quietly running two full-time remote jobs, and both come with a 401(k) that matches. He does what any diligent saver would do: he logs into each provider and sets his contribution to max out the plan. By December he has put away well over forty thousand dollars in pretax deferrals and feels good about it. What he has actually done is break a single, person-level limit twice over, and unless he catches it before April 15 the IRS will tax the overage not once but twice. The 401(k) is the most common benefit in the Overemployed playbook and the easiest place to create a quiet, expensive mistake.

The number that matters is the elective deferral limit under IRC §402(g). For 2026 it is $24,500, plus an $8,000 catch-up at age 50 and over, and a larger $11,250 catch-up for ages 60 through 63. The critical word is yours. The limit attaches to you, the taxpayer, across every 401(k) and 403(b) you participate in during the year, and it does not reset when you walk into a second employer's plan. Roth and pretax deferrals both count against it. A plan can only police its own contributions; it has no window into the deferrals you are making at another company, so each plan will happily let you contribute up to its own ceiling while you sail through the only ceiling that counts.

An excess deferral is one of the rare things in the code that is genuinely taxed twice. The dollars you over-defer are added back to your wages and taxed in the year you contributed them, because they were never eligible for the exclusion in the first place. Then, because that money sits inside a pretax 401(k) with no basis, it is taxed again when it eventually comes out in retirement, along with all the growth in between. The escape hatch is narrow. You have to ask one of the plans for a corrective distribution of the excess, plus the earnings it generated, and you have to do it by April 15 of the following year, a deadline the IRS 401(k) fix-it guidance spells out plainly. Miss that date and the corrective distribution is off the table; the double tax is locked in.

The same structure that creates the trap also creates an opportunity, because a different limit works in your favor. The annual additions limit under IRC §415(c), $72,000 for 2026, applies per unrelated employer, not per person. Your $24,500 of deferrals is shared across both plans, but each unrelated employer's plan gets its own $72,000 bucket to hold deferrals, the employer match, profit sharing, and after-tax contributions. Two genuinely unrelated employers mean two separate $72,000 ceilings, and that is where an Overemployed saver can pull ahead of a single-job colleague rather than fall behind.

The reliable win is the match. Free money sits at both jobs, but you can only claim each employer's match by actually deferring into that employer's plan, and your total deferrals are still capped at $24,500. So the move is to split, not to stack. Defer enough into J1 to capture J1's full match, defer enough into J2 to capture J2's full match, and keep the combined figure at or under the limit. Pour the whole $24,500 into one plan and you may walk away from thousands of dollars of match at the other. If both plans also allow after-tax contributions with in-plan Roth conversions, you have two independent mega-backdoor-Roth lanes, each under its own $72,000 limit, though many plans do not offer that feature, so confirm it before you count on it.

If you already over-deferred, the correction is mechanical but time-sensitive. Identify the excess by adding the elective deferrals reported in box 12 of every W-2, code D for pretax and codes AA or EE for Roth, and subtract the year's limit. Then contact one of the plan administrators in writing and request a corrective distribution of the excess amount plus allocable earnings, citing the §402(g) limit, before April 15. If that date is close, book a free intro call and we will handle the request so it lands in time. The one thing that does not work is hoping the providers sort it out for you. They will not, because from where each of them sits, nothing is wrong.

Two W-2 jobs change almost every limit on a tax return, and the 401(k) is only the first one. The same year that produces an excess deferral usually produces an excess Social Security credit and an under-withholding problem at the same time, and they are far easier to catch when someone is looking at both W-2s at once.