What Happens to Your 401(k) When You Sell Your Business?

Most business owners spend years building a 401(k) plan for themselves and their employees — maximizing contributions, profiting from employer matches, building a retirement cushion. When the sale closes, that plan doesn't simply transfer to the buyer. Whether it terminates, merges into the buyer's plan, or continues depends almost entirely on your deal structure. And what you do with your own balance in the 12 months after the sale can affect your tax bill for decades. Here's the 2026 framework.

Why the 401(k) doesn't just "go with the business"

A 401(k) plan is sponsored by the employer entity, not by the business's assets. When you sell, the plan's future depends on what survives the transaction.

• In an asset sale, the buyer acquires the company's assets — equipment, IP, customer contracts — but not the legal entity. Since the entity (and therefore the plan sponsorship) stays with you, the buyer starts fresh. The old plan has no home in the new structure, and must either be terminated before closing or continued briefly while you wind it down.
• In a stock sale, the buyer acquires the entity itself — the corporation or LLC that was the plan sponsor. The plan legally continues inside that entity. The buyer now owns a plan they didn't design and may not want, so the typical path is to merge it into their own plan or terminate it post-close.

This distinction matters because it affects the timing of your decision, who is responsible for the plan's administration after closing, and what your options are for your own account balance.

Asset sale: you own the plan termination problem

In an asset sale, you — the seller — retain the 401(k) plan. The buyer has no obligation to continue it or take any action related to it. You have two choices:¹

1. Terminate the plan before or at closing. This is the most common approach. You adopt a board resolution setting a plan termination date, notify participants, distribute all account balances (including your own), and file a final Form 5500 (typically with a "short plan year"). Most TPAs charge a plan termination fee of $1,500–$4,000 depending on plan complexity and participant count.
2. Continue the plan temporarily post-closing. Technically possible if you remain an operating entity (e.g., you're holding a seller note and have ongoing business activity), but this creates nondiscrimination testing problems almost immediately. Once the employees are gone, the plan may fail ADP/ACP tests. In practice, virtually all sellers in asset transactions terminate the plan at or shortly after closing.

The vesting trap: 100% vesting required at plan termination

The moment you adopt the plan termination resolution, every participant — including employees who would normally forfeit unvested balances when they leave — becomes 100% vested in their account balance. ERISA's partial termination rules require full vesting when a plan terminates or when a significant portion of covered employees are severed (generally 20%+).¹

This matters for your bottom line because any unvested employer contributions that were earmarked for forfeiture — and that you may have been counting on to reduce future contributions — instead go to those employees. On a plan with significant unvested employer match balances, this can be a meaningful surprise. Factor it into your pre-sale planning; if the plan has large unvested balances, terminating the plan before the triggering layoffs may allow a different vesting schedule to apply. This is a nuance worth discussing with your plan TPA and an ERISA counsel.

The $7,000 forced rollover threshold (SECURE 2.0)

When distributing terminated plan balances to former participants, plans can involuntarily cash out accounts below a certain threshold — previously $5,000, raised to $7,000 by SECURE 2.0 (effective 2024). Accounts above $7,000 must wait until the participant affirmatively requests a distribution or rollover; you cannot simply cut a check and mail it.² Participants with balances between $1,000 and $7,000 must receive an automatic IRA rollover (to a safe harbor IRA the plan selects) rather than a cash payout, unless they direct otherwise.

Stock sale: the plan follows the entity

In a stock sale, the buyer acquires the entity that sponsors the plan. Legally, nothing has changed about the plan — the same employer exists, just under different ownership. The buyer now has three options:¹

As the seller in a stock transaction, your negotiating interest is in getting the plan treatment clearly documented in the purchase agreement. Don't leave it to post-close negotiation. Specify (a) whether your plan will merge or terminate, (b) who bears the termination costs if applicable, and (c) what happens to any unvested employer contributions at the termination date (which, again, fully vest).

Your personal 401(k) balance: three options

As the business owner, you are also a participant in the plan. Your account balance — often the largest in the plan — is subject to the same termination or distribution mechanics as everyone else's. But you have more time and flexibility to decide how to take it.

Option 1: IRA rollover (most common)

A direct rollover to a traditional IRA preserves the tax deferral on your full account balance. You transfer the assets trustee-to-trustee; no taxes are withheld and no 10% early withdrawal penalty applies regardless of your age. The IRA can hold the same investments or be invested however you choose — including a brokerage IRA with broad investment options that may exceed what your 401(k) offered.³

Rolling to a traditional IRA defers the tax problem — it doesn't solve it. The full balance will eventually be taxed as ordinary income when you take distributions, or when RMDs begin at age 73 (born 1951–1959) or 75 (born 1960+) under SECURE 2.0.⁴ This is why many sellers choose a Roth conversion strategy instead of — or in addition to — a straight IRA rollover.

Option 2: Roth conversion (often optimal in the post-sale window)

For most business owners, the year of the sale — and potentially the two to three years immediately following — represents the best Roth conversion opportunity of their lifetime. Here's why.

In the year of the sale, your MAGI is enormous. But in subsequent years — after the deal closes, before Social Security starts, and before RMDs kick in — your taxable income may drop to near zero. There is no business income. Salary income is gone. You're living off investment returns, perhaps some installment sale proceeds, and drawing down cash. In that gap, your marginal tax bracket may be 12% or 22% rather than the 32%–37% you paid as an active business owner, and the same 32%–37% you'll eventually pay on forced RMDs at 73 or 75.⁴

The strategy: roll your 401(k) balance to a traditional IRA, then convert portions of it to a Roth IRA in each low-income year — filling the 22% or 24% bracket and stopping before hitting 32%. You pay ordinary income tax on each conversion at today's lower rate; the converted amount then grows and is withdrawn tax-free.

Use the Roth conversion optimizer on this site to model the annual conversion amounts, cumulative tax cost, and estimated lifetime savings for your specific balance, age, and income profile.

Option 3: Take a taxable distribution (usually the wrong choice)

You can elect to take your 401(k) balance as a cash distribution. The plan withholds 20% for federal taxes, and you report the full amount as ordinary income in the distribution year — on top of the business sale proceeds. At a 37% marginal rate, a $500,000 401(k) distribution in the sale year generates approximately $185,000 in federal income tax. Add state income tax and you may keep 50–55 cents on the dollar.

The Rule of 55 exception: If you separate from service (which includes selling the business and ceasing employment) in the calendar year you turn 55 or later, distributions from that employer's plan are exempt from the 10% early withdrawal penalty under IRC § 72(t)(2)(A)(v).³ This avoids the penalty but does not avoid ordinary income tax. Note that the Rule of 55 applies only to the plan from which you're separating — not to IRAs. If you roll the balance to an IRA first and then take distributions before age 59½, the Rule of 55 no longer protects you, and you'd need a different exception.

Taking a full distribution rarely makes financial sense. The main exception: a seller with large capital loss carryforwards, significant charitable contribution deductions, or a year in which a 401(k) distribution would be absorbed at a low marginal rate. Those cases require specific modeling.

2026 contribution limit context

If you are still operating your business during the year of the sale and the plan is active for part of the year, you may be entitled to make final contributions before termination. The 2026 limits:⁵

• Employee deferral: $24,500 (under 50), $32,500 (age 50–59 catch-up), $35,750 (age 60–63 super catch-up under SECURE 2.0 § 109)
• Total annual additions limit (§ 415(c)): $72,000 per participant (excludes catch-up contributions)
• Employer profit-sharing contribution: Up to 25% of W-2 compensation, combined with deferrals not to exceed $72,000

For a seller-owner who closes mid-year, pro-rating the employer contribution based on compensation paid through the termination date can still result in a meaningful deduction. Coordinate the final contribution and the plan termination date — you generally cannot make new employer contributions after the plan termination date.

Cash balance and defined benefit plans: different rules

If you also maintained a cash balance plan or traditional defined benefit plan alongside the 401(k), the rules are stricter. Defined benefit plans are governed by PBGC insurance requirements and ERISA § 204(h), which requires 45-day advance notice to participants before a significant benefit reduction (including termination). The process takes longer — typically 6–12 months for a standard termination — and requires a plan actuary to certify that assets are sufficient to cover all accrued benefits.

A cash balance plan termination in connection with a business sale is specifically recognized under the "business sale exception" to the plan permanency rule, which would otherwise prevent terminating a plan shortly after establishing it. But you must still follow the PBGC termination procedures and the § 204(h) notice timeline. Factor this into your sale timeline — starting the termination process 6–9 months before the expected close date is advisable for plans with large DB or cash balance balances.

SECURE 2.0 changes that affect post-sale planning

Several SECURE 2.0 provisions are directly relevant for business sellers managing inherited or transferred 401(k) balances:⁴

• Roth 401(k) lifetime RMDs eliminated (§ 325, effective 2024). Roth accounts inside 401(k) plans are no longer subject to lifetime required minimum distributions starting in 2024. If your 401(k) has a Roth component, rolling it to a Roth IRA preserves the same no-RMD benefit with more investment flexibility.
• RMD age 73 and 75 (§ 107). If you were born 1951–1959, RMDs begin at 73. Born 1960 or later, RMDs begin at 75. The post-sale Roth conversion window extends until the RMD start date — the longer the window, the more conversion capacity you have at low rates.
• Super catch-up contributions (§ 109). Ages 60–63 may contribute an additional catch-up beyond the standard $8,000 catch-up — the super catch-up is $11,250 for 2026 (the greater of $10,000 or 150% of the standard catch-up). If your plan is still active when you close and you're in this age range, confirm the final year contribution maximizes this provision before termination.
• 529-to-Roth rollover (§ 126). Limited relevance here, but a provision that may affect post-sale estate planning if you have 529 plans with excess balances post-college-funding.

Plan administration checklist for sellers

Before the sale closes:

1. Notify your TPA 90–120 days before expected closing. Asset sales especially: they need time to prepare the termination resolution, participant notices, distribution paperwork, and Form 5500 filing schedule.
2. Check for outstanding participant loans. Outstanding loan balances become taxable distributions at plan termination if participants can't repay them. Notify affected participants early — they may want to repay the loan in cash to avoid the tax hit.
3. Map unvested employer match balances. These fully vest at termination. Know the dollar amount so you're not surprised at closing.
4. Determine your own rollover destination before distributions begin. Open the receiving IRA at your custodian of choice before the plan terminates so the direct rollover can be processed immediately.
5. Coordinate with your CPA on the sale-year tax picture. Adding a $500K+ 401(k) conversion to an already large sale-year income can push you into the highest IRMAA tiers for 2028–2029 (see IRMAA guide) and maximize your NIIT exposure. Timing the rollover to a traditional IRA — and then executing Roth conversions in the lower-income years that follow — is typically the better approach.

The coordination argument for a fee-only advisor

The plan termination mechanics are handled by your TPA and ERISA counsel. But the decision about what to do with your personal balance — IRA rollover, Roth conversion strategy, timing relative to IRMAA, coordination with installment sale income, estate planning implications — sits exactly at the intersection of exit planning and investment/tax planning that most CPAs and M&A advisors aren't focused on.

A fee-only exit-planning specialist models the full picture: the sale proceeds, the 401(k) balance, the post-sale income stream (installment payments, investment income, Social Security timing), and the RMD trajectory at 73/75. Running the conversion math without that full picture is guessing. Running it with the full picture can save $100,000–$500,000+ in taxes over a 20-year retirement for a seller with a $1M+ 401(k) balance.

See also: post-sale financial planning guide and the Roth conversion optimizer.

Sources

1. IRS — 401(k) Plan Termination. Asset sale vs. stock sale mechanics; plan termination process; 100% vesting requirement; final Form 5500 filing; distribution requirements at termination.
2. IRS — Retirement Plans FAQs Regarding Plan Terminations. Mandatory distributions, forced rollover threshold (raised to $7,000 by SECURE 2.0 effective 2024), timing rules, outstanding loan treatment at termination.
3. IRS — Retirement Topics: Termination of Employment. IRA rollover mechanics, 60-day rollover window, 20% withholding on indirect distributions, Rule of 55 exception under IRC § 72(t)(2)(A)(v), direct rollover process.
4. IRS — SECURE 2.0 Act of 2022. § 107 RMD age 73/75; § 109 super catch-up contributions ages 60–63; § 325 elimination of Roth 401(k) lifetime RMDs effective 2024; § 115 forced rollover threshold increase to $7,000.
5. IRS Notice 2025-67 — 2026 Benefit and Retirement Plan Limits. 2026 401(k) employee deferral limit: $24,500; catch-up (age 50+): $8,000; super catch-up (ages 60–63): $11,250; § 415(c) annual additions limit: $72,000. IRA contribution limit: $7,500.

401(k) plan termination rules reflect ERISA and IRS requirements as of 2026. SECURE 2.0 (signed December 2022) changes effective 2024 include Roth 401(k) lifetime RMD elimination, $7,000 forced-rollover threshold, and super catch-up contributions. RMD ages 73/75 per SECURE 2.0 § 107. Contribution limits from IRS Notice 2025-67. Rule of 55 per IRC § 72(t)(2)(A)(v). Values verified June 2026. Plan terminations involve entity-specific facts; confirm procedures with your plan TPA and an ERISA attorney before adopting a termination resolution.