Employers ending a 401(k) plan have to hit several written-notice obligations before assets go out the door: a participant notice announcing the termination and full vesting, a Section 402(f) tax notice delivered 30 to 180 days before any distribution, a supplemental safe harbor notice if the plan is ending mid-year, written notice of any automatic IRA rollover for small balances, and government filings on the back end. The 401(k) plan termination notice requirements do not include the 60-to-90-day advance participant notice that many employers assume applies. That rule belongs to PBGC-covered defined benefit plans. For a defined contribution plan, the obligations come from ERISA’s fiduciary duties, the plan document itself, and specific Internal Revenue Code provisions tied to distributions.
Set the Termination Date First
Notices cannot be drafted properly until the employer formally establishes when the plan ends. The IRS treats a 401(k) plan as terminated only when three things happen: a termination date is set, benefits and liabilities are fixed as of that date, and all assets are distributed as soon as administratively feasible.1Internal Revenue Service. 401(k) Plan Termination The date is usually set by a board resolution, a plan amendment, or a complete discontinuance of contributions.
A board resolution is the common route. It should name the exact termination date, direct that employer and employee contributions stop, and instruct the administrator to begin distributions. The plan document itself has to be amended too, and that amendment must provide for 100% vesting of all participant accounts as of the termination date. Under the Internal Revenue Code, a plan cannot stay qualified unless all accrued benefits become nonforfeitable on termination.2Office of the Law Revision Counsel. 26 USC 411 – Minimum Vesting Standards Any unvested employer match or profit-sharing money a participant would have forfeited becomes theirs.
Written Notice to Participants
Here is the point where employers most often overcorrect. There is no statute in the Internal Revenue Code or ERISA that requires a 60-day or 90-day advance participant notice before terminating a 401(k) plan. That window applies to a different regime for PBGC-covered defined benefit plans. For a 401(k), the obligation is the more general one: ERISA’s fiduciary duty rules require participants to receive timely, adequate information about material changes to their benefits, and whatever notice provisions live inside the plan document are binding on the sponsor.
Even without a fixed statutory deadline, written notice well ahead of the termination date is standard practice. The notice should go to all active participants, former participants with balances, and beneficiaries, and it should cover:
- Plan name, plan number, and employer identification number.
- The specific termination date.
- The date after which no further deferrals or employer contributions will be accepted.
- A clear statement that all accounts become 100% vested on the termination date.
- A general description of when and how distributions will be made.
- Contact information for questions.
Spell out the vesting piece plainly. Participants who assume they are walking away from an unvested match need to know they are not.
Extra Notice Rules for Safe Harbor Plans
Terminating a safe harbor 401(k) mid-year triggers an additional notice on top of the general participant communication. Reducing or suspending safe harbor contributions before the plan year ends counts as a mid-year change, which requires a supplemental safe harbor notice describing the change and its effective date. The IRS treats a distribution window of 30 to 90 days before the effective date as reasonable.3Internal Revenue Service. Mid-Year Changes to Safe Harbor 401(k) Plans and Notices
Participants also need a reasonable chance to change their deferral elections after they learn about the change but before it takes effect. A 30-day election window satisfies that requirement.3Internal Revenue Service. Mid-Year Changes to Safe Harbor 401(k) Plans and Notices Sponsors who want to avoid the supplemental notice and election reopening can wait and terminate at the end of the plan year instead.
The 402(f) Tax Notice Before Any Distribution
Before any account is paid out, the plan administrator has to give the participant a separate written explanation of the tax rules. That is the Section 402(f) notice, sometimes called the special tax notice or rollover notice. It has to cover the right to roll funds into an IRA or another employer’s plan, the mandatory 20% federal income tax withholding on distributions not directly rolled over, and the 10% early withdrawal penalty that can apply to participants under age 59½.4eCFR. 26 CFR 1.402(f)-1 – Required Explanation of Eligible Rollover Distributions
Timing is specific. The 402(f) notice must reach the participant no fewer than 30 days and no more than 180 days before the distribution date.5Internal Revenue Service. Notice 2026-13 – Safe Harbor Explanations Eligible Rollover Distributions A participant can affirmatively waive the 30-day waiting period and take the distribution sooner. The IRS publishes model 402(f) language, most recently in Notice 2026-13, which most administrators use verbatim.
Notice for Small-Balance Automatic Rollovers
Participants who do not respond with a distribution election create a separate notice obligation. Plans may distribute a vested balance without consent if it is at or below $7,000, a threshold Section 304 of the SECURE 2.0 Act raised from $5,000 for distributions after December 31, 2023. The mechanics split by size:
- $1,000 or less: the plan can cut a direct cash payment to the participant.
- Over $1,000 and up to $7,000: if the participant does not elect a direct payment or a rollover, the administrator must roll the money into an IRA opened in the participant’s name and give the participant written notice that the rollover has been made.6Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
Balances above $7,000 require the participant’s actual consent. A plan cannot force those out, and it cannot close until every one of those accounts is resolved.
Missing Participants Still Have to Be Noticed
The notice obligation extends to people the plan administrator cannot locate. A plan cannot finish terminating until every balance is distributed, so the Department of Labor has set minimum search steps that fiduciaries of terminating defined contribution plans must take:
- Send a certified-mail notice to the last known address.
- Check employer records and any related-plan records.
- Contact the participant’s designated beneficiary for updated information.
- Use free electronic search tools, including internet searches and public records databases.
These steps are mandatory, and each attempt should be documented.7Internal Revenue Service. Missing Participants or Beneficiaries When searches fail, small balances typically go into an IRA opened in the participant’s name, and larger unclaimed amounts can go to a state unclaimed property fund or to the PBGC’s voluntary Missing Participants Program for defined contribution plans.
Government Filings That Follow the Notices
Once distributions are complete, filings close out the plan. The final Form 5500, Annual Return/Report of Employee Benefit Plan, is not optional. Every terminating plan files one for the short plan year ending when all assets are distributed, marked as a final return only in the year the last assets are paid out.8Internal Revenue Service. Form 5500 Plan Terminations Without a Form 5310 Filing The deadline is the last day of the seventh month after the plan year closes.
Form 5310, Application for Determination for Terminating Plan, is optional but commonly filed. It asks the IRS to confirm in writing that the plan stayed qualified through termination, which gives the employer documented protection instead of a self-certification.9Internal Revenue Service. About Form 5310, Application for Determination for Terminating Plan The user fee is $4,500, and the form is filed electronically through Pay.gov.
Also worth flagging: the IRS reads “as soon as administratively feasible” to mean within one year of the termination date, and a plan that has not distributed all assets by then is treated as ongoing and must keep meeting every qualification requirement.10Internal Revenue Service. Plan Termination – Failure to Timely Distribute Assets
Penalties for Missing a Notice or Filing
The exposure is real. DOL penalties for a late or missing Form 5500 can run up to $2,739 per day with no statutory maximum. The IRS layers on its own $250-per-day penalty, capped at $150,000 per plan per year.11Internal Revenue Service. Penalty Relief Program for Form 5500-EZ Late Filers Both can hit at the same time.
Sponsors who catch the miss before the DOL does have a safety valve. The Delinquent Filer Voluntary Compliance Program cuts the penalty to $10 per day, capped at $750 per filing for small plans and $2,000 per filing for large plans.12U.S. Department of Labor. Delinquent Filer Voluntary Compliance Program Once the DOL sends a notice, the program is no longer available.
The larger risk sits behind the filing penalties. Failing to fully vest participants, skipping the 402(f) notice, or leaving assets undistributed past the one-year window can each trigger disqualification. A disqualified plan means employer contributions lose their deduction and participants face immediate tax on their balances.