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Solo 401(k) $250,000 threshold for Form 5500-EZ

How the IRS $250,000 one-participant plan asset threshold works for Solo 401(k) Form 5500-EZ filing.

By Yann LephayPublished 2026-05-15 · Updated 2026-05-15

Summary

The Solo 401(k) $250,000 threshold is measured at year end across all one-participant plans maintained by the same employer. If the combined total is more than $250,000, Form 5500-EZ is generally required for each one-participant plan. If the combined total is $250,000 or less, an ongoing plan usually does not file, unless it is the final plan year.

The $250,000 threshold is combined across one-participant plans, not tested plan-by-plan.

ThresholdMore than $250,000Measured using combined end-of-year one-participant plan assets.
Not per planAggregate same-employer one-participant plansA small second plan can push both plans into the filing lane.
Exception to exceptionFinal returnA final plan year can require Form 5500-EZ even below $250,000.

Use the end-of-year combined asset number

Start with the year-end value for this Solo 401(k), then add the year-end assets of any other one-participant plans maintained by the same employer. The test is not per brokerage account, per participant, or per plan in isolation.

Example: two small plans can still trigger filing

If Plan A has $200,000 at year end and Plan B has $53,000 at year end, the combined one-participant plan asset total is $253,000. That is over the IRS threshold, so the sponsor should evaluate Form 5500-EZ for each one-participant plan rather than assuming each plan is under the limit.

Final year is checked separately

The threshold does not remove the final-return rule. If all plan assets were distributed or transferred during the final plan year, the sponsor should evaluate a final Form 5500-EZ even when the ending combined asset amount is at or below $250,000.

What Solo 5500 Desk prepares

Solo 5500 Desk captures the threshold facts, final-year flag, filing-method warning, source-record checklist, Form 5500-EZ answer packet, and annual passport. The user reviews the packet and files through the official paper or EFAST2 path.

When to use a professional

Use a CPA, EA, attorney, TPA, or official IRS/DOL instructions when asset values are hard to determine, the case is late or amended, there is an IRS notice, the business has non-owner employee issues, or controlled group and plan-administration questions are involved.

Common questions

Is the Solo 401(k) $250,000 threshold per account?

No. The IRS threshold is based on the combined end-of-year assets of the one-participant plan and any other one-participant plans maintained by the same employer.

Do I file Form 5500-EZ at exactly $250,000?

The ordinary annual filing trigger is more than $250,000 in combined one-participant plan assets at year end. A final plan year can still require a return at or below that amount.

What happens if I have two one-participant plans?

Add the end-of-year assets of all one-participant plans maintained by the employer. If the combined total is over $250,000, each plan in that lane may need its own Form 5500-EZ.

Can Solo 5500 Desk value hard-to-price assets for the threshold?

No. The product expects source-supported year-end statement values. Private investments, employer real estate, hard-to-value assets, and nonzero liabilities are outside scope.

Official sources

IRS Form 5500-EZ filing noticesIRS states the $250,000 asset exception and the last-day-of-the-7th-month deadline. Official source reviewed for this MVP on May 2, 2026.IRS Instructions for Form 5500-EZOfficial instructions explain combined one-participant plan assets, final returns, and electronic filing requirements. Official source reviewed for this MVP on May 2, 2026.IRS one-participant plan project resultsIRS describes common one-participant plan filing mistakes, final-year filings, and failure-to-file penalties. Official source reviewed for this MVP on May 2, 2026.IRS mandatory electronic filing for Forms 8955-SSA and 5500-EZOfficial IRS guidance on the 10-return mandatory e-filing threshold and aggregation rules. Official source reviewed for this MVP on May 2, 2026.DOL EFAST2 filer helpOfficial DOL guidance on electronic filing, IFILE, credentials, and approved software requirements. Official source reviewed for this MVP on May 2, 2026.IRS Form 5558 extensionOfficial extension form context for Form 5500-series returns. Official source reviewed for this MVP on May 2, 2026.