What happens to your 401(k) when you leave a job?
Last updated August 2026
Short answer
The default is inaction, and inaction is a legitimate choice here. The costly mistakes are cashing out and rolling too quickly.
What is yours
Every dollar you contributed is yours immediately and always has been.
Employer contributions are yours to the extent they have vested, and vesting schedules differ widely between plans.
Anything unvested is forfeited on separation, which is why leaving a few months before a vesting date can be an expensive convenience.
The four options
Leave it, which costs nothing and is often right if the plan has institutional pricing.
Roll it to the new employer's plan, which consolidates and keeps pre-tax money out of IRAs for backdoor Roth purposes.
Roll it to an IRA for full investment choice, or cash it out, which is the only option that permanently destroys value.
Small balances can be forced out
Plans may automatically roll balances below a regulated threshold into an IRA chosen by the plan.
Very small balances can be distributed in cash, with the tax consequences that implies.
Those automatic IRAs frequently sit in cash-like investments for years, which is one reason old small balances quietly stop growing.
Try it in Walnut
Walnut connects to your brokerage and reads what you hold, so a rolled-over balance appears alongside everything else rather than as another forgotten login.
Loans accelerate
Most plans require an outstanding loan to be repaid shortly after separation.
An unpaid balance becomes a deemed distribution, taxable and generally subject to the additional tax.
You may be able to contribute an amount equal to the offset to an IRA by the tax filing deadline, which avoids the tax if the cash can be found.
The rule of 55
Separating in or after the calendar year you turn 55 unlocks penalty-free access to that employer's plan.
Income tax still applies. What disappears is the 10% additional tax.
Rolling to an IRA removes the exemption, so anyone who might need the money before 59.5 should leave it in the plan.
What to do in the first month
Download a statement, note the recordkeeper and confirm your address and beneficiaries are current.
Check the vesting position and whether any loan is outstanding.
Then take your time on the rollover decision, which is easier to make well once the fee disclosures of both plans have been read.
Do not lose track of it
Old plans are forgotten constantly, and employers change recordkeepers, so the provider name on the statement may not be the one holding it in five years.
Keeping a note of the plan, the recordkeeper and the account number is enough to avoid a search later.
The Department of Labor and the PBGC both operate searches for abandoned plans and unclaimed benefits, which exist because this happens at scale.
Sources
Distribution and rollover rules, loan offsets and the exceptions to the additional tax are published by the IRS at Rollovers of retirement plan and IRA distributions and Exceptions to tax on early distributions. Vesting is covered by the Department of Labor at Types of Retirement Plans. Walnut is informational and is not an investment adviser. This guide is educational and not personalized tax advice.
FAQ
What happens to my 401(k) when I leave?
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It stays where it is unless you act or the balance is small enough for the plan to force it out. Your own contributions and vested employer money remain yours; anything unvested is forfeited on separation.
What are my four options?
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Leave it in the old plan, roll it to the new employer's plan, roll it to an IRA, or cash it out. Cashing out is the expensive one, since it triggers income tax and generally a 10% additional tax below 59.5.
Can the plan force me out?
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Yes, for small balances. Plans can automatically roll balances below a regulated threshold into an IRA, and very small ones can be cashed out. That is why a job you left a decade ago may no longer hold what you remember.
What happens to my loan?
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Leaving usually accelerates repayment. An unpaid balance is treated as a distribution, taxable and generally penalised, though you may be able to contribute an equal amount to an IRA by the tax filing deadline to avoid the tax.
Do I lose the employer match?
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Only the unvested part. Vesting schedules vary, and leaving before you are fully vested forfeits the remainder immediately, which is worth checking against your departure date before resigning.
Does the rule of 55 apply?
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If you separate in or after the calendar year you turn 55, withdrawals from that employer's plan avoid the 10% additional tax. Rolling the balance to an IRA destroys that, which is a reason not to consolidate immediately.
What about company stock?
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Net unrealised appreciation rules may allow the growth on employer stock to be taxed at long-term capital gains rates rather than as ordinary income, and a rollover generally forfeits that. Take advice before moving it.
Is there a deadline to decide?
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Generally no, for balances above the force-out threshold. That means the comparison of fees and features can be made carefully rather than in the week you leave.
How do I avoid losing track of it?
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Keep a note of the plan name, the recordkeeper and the account number, and update your address when you move. Employers change providers, so the name on today's statement may not be the one holding it in five years, which is why federal search tools for lost plans exist at all.