A Problem Measured in Trillions
Most retirement coverage focuses on how much you contribute. A far less discussed number is how much simply gets left behind.
According to an analysis by Capitalize, roughly 31.9 million forgotten 401(k) accounts now hold about $2.1 trillion in assets — an average of roughly $66,691 per account, up from $56,616 in the prior study. The flow is accelerating rather than slowing: an estimated 3.5 million accounts were left behind in 2023, 4.0 million in 2024, and about 4.2 million in 2025.
Capitalize estimates these stranded accounts could cost savers up to $115 billion annually through higher fees and poorly allocated investments.
Why Small Balances Disappear
The damage is concentrated at the low end. Research from the Employee Benefit Research Institute identified roughly $92.4 billion in annual 401(k) cash-out leakage, and found that participants with balances under $7,000 cash out at rates approaching 60% when they change jobs.
That $7,000 figure is not a coincidence. Section 304 of the SECURE 2.0 Act raised the statutory mandatory cash-out limit from $5,000 to $7,000 for distributions made after December 31, 2023. Plans may — at the sponsor's discretion — force small balances out of the plan after an employee leaves. The mechanics:
- Vested balances over $7,000 must stay in the plan unless you act.
- Balances between $1,000 and $7,000 are rolled into a safe-harbor IRA chosen by the plan.
- Balances of $1,000 or less can be paid out as a lump sum.
A forced lump sum is a taxable distribution. Under age 59½, it typically carries income tax plus a 10% early withdrawal penalty. And a safe-harbor IRA is not a neutral parking spot — these accounts are frequently defaulted into conservative, low-yield investments while fees erode the balance.
What Auto Portability Actually Does
Auto portability is designed to interrupt that chain. Instead of a small balance being cashed out or stranded in a safe-harbor IRA, the account is automatically located and transferred into the participant's new employer's plan.
The infrastructure comes from the Portability Services Network (PSN), operational since late 2023. Its founding members — Alight, Empower, Fidelity, Principal, Vanguard, and TIAA — represent more than 82 million workers across over 185,000 employer-sponsored plans.
Adoption, however, is still early. A Vanguard analysis cited by PlanSponsor in February 2026 found that by year-end 2025, only 7% of plans had adopted auto portability. Industry reporting in 2026 suggests larger plans are now joining in meaningful numbers as sponsors complete due diligence — an inflection point, but not yet the default.
Practical Takeaways
- Do not wait for the feature to find you. With adoption at 7%, the odds that both your old and new plan participate are still low. Treat consolidation as your job, not the system's.
- Inventory every former employer. List each job going back to your first 401(k)-eligible role. The average forgotten account holds nearly $67,000 — this is rarely trivial money.
- Act before the force-out. If a balance sits under $7,000 at a former employer, you may have limited time before the plan distributes it for you. A direct rollover you initiate preserves tax deferral; a forced cash-out may not.
- Insist on a direct rollover. Have funds moved trustee-to-trustee. An indirect rollover triggers 20% mandatory withholding and a 60-day clock to redeposit the full amount, including the withheld portion.
- Check whether you already have a safe-harbor IRA. If a past employer force-transferred a balance, the account exists somewhere in your name. Compare its fees and allocation against your current options before leaving it alone.
- Ask your HR department directly. A simple question — "Does our plan participate in auto portability?" — tells you whether future job changes will be handled automatically.
For retirement-focused investors, the lesson is structural. A $6,000 balance cashed out at 30 is not a $6,000 mistake; it is decades of forgone compounding, minus taxes and a penalty. Auto portability is a genuine improvement to the plumbing of the U.S. retirement system — but until adoption broadens well past 7%, the most reliable portability mechanism remains the one you execute yourself.
Sources: Capitalize – The True Cost of Forgotten 401(k)s (September 2025 analysis); Employee Benefit Research Institute (EBRI) – 401(k) Cash-Out Leakage Study; Portability Services Network, LLC; Retirement Clearinghouse – Auto Portability Recent Developments; Vanguard analysis via PlanSponsor (February 2026); Milliman – SECURE 2.0 Mandatory Cash-Out Limit Increase; Foley & Lardner LLP – Automatic Cash-Out Limits Under SECURE 2.0.