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Loophole

Mega Backdoor Roth — $46,500 Extra to Roth via After-Tax 401(k)

If your 401(k) allows after-tax contributions + in-plan Roth conversions, funnel up to $46,500/yr into Roth.

Overview

2024 total 401(k) limit is $69K ($76.5K age 50+). After employee deferral ($23K) + employer match, remaining space can be filled with AFTER-TAX (not Roth) contributions, then converted in-plan to Roth (or in-service distributed to a Roth IRA). Total incremental Roth contribution: up to $46,500/yr. Requires plan to allow both (1) after-tax contributions and (2) in-plan Roth conversions or in-service withdrawals. Solo 401(k)s can be custom-designed to allow this. Over 20 years, $46K/yr at 8% = $2.3M tax-free.

Best fit
High earners with generous 401(k) plansSolo 401(k) owners with custom plan docsFIRE-focused savers
Estimated impact
$46,500/yr → $2M+ tax-free over 20 years

Click Generate advisory deep dive for mechanics, IRC citations, a step-by-step execution plan, a worked numeric example on your profile, costs, risks, and this-week actions.

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