Part of the Retirement Planning guide.
The rest of this guide assumes you’re actively self-employed and contributing. This is the part nobody plans for: what happens to the account itself if you take a W-2 job, hire employees, or close the business entirely.
The Trigger: You No Longer Qualify
A Solo 401(k) requires that the only participants be you (and a spouse, if applicable) — no other employees. If your business grows to include a full-time employee who becomes eligible to participate (generally after one year of service, or two consecutive years of 500+ hours), your plan no longer meets the eligibility rules, and you have to act. The same applies if you simply stop being self-employed and take a W-2 position with no freelance income continuing.
Your Real Options
Roll it into an IRA. The most common path. Done as a direct trustee-to-trustee transfer, this is non-taxable. Funds can go into a Traditional IRA, a Roth IRA, or both, depending on which bucket the money came from in the original plan.
Roll it into your new employer’s 401(k), if they accept incoming rollovers. Not all plans do — worth confirming with the new employer’s plan administrator before assuming this is available.
Convert to a full employer 401(k), if your business is growing rather than closing. If you’re adding staff and want to keep offering a retirement plan, some businesses restate the Solo 401(k) into a standard employer plan instead of closing it. Since the plan isn’t being terminated, this route doesn’t require the closure paperwork below.
The Paperwork Almost Nobody Knows About: Form 5500-EZ
This is the part that catches people off guard, sometimes years later. If your Solo 401(k) ever held more than $250,000 at the end of any plan year, you’ve had an ongoing annual filing requirement (Form 5500-EZ) that many solo filers never realize applies to them. And regardless of whether you ever crossed that threshold, a final Form 5500-EZ is required when you close the plan — even if the balance was always under $250,000.
The IRS statutory penalty for missing this is $250 per day, capped at $50,000 per return — under IRC §6652(e). This still isn’t a minor administrative fee, but if you catch it before the IRS catches it first, there’s a real, manageable way out: the IRS Penalty Relief Program for late Form 5500-EZ filings (Rev. Proc. 2015-32) lets you submit the late form voluntarily and bypasses the daily-penalty calculation entirely — replacing it with a flat $500 per late return, capped at $1,500 per plan. This only works if you get ahead of it yourself; once an IRS enforcement letter arrives, this relief program is no longer available. If you’ve missed a Form 5500-EZ filing, the priority is filing under this program before the IRS finds it first, not after.
The final filing has its own strict deadline, separate from your tax return. It’s due by the last day of the seventh month following the month the plan was terminated — not tied to your personal or business tax filing date. If you close the business and liquidate the account on October 15, your final Form 5500-EZ is due by May 31 of the following year. Mark this on its own calendar reminder; it’s easy to lose track of since it doesn’t align with any other filing deadline you’re used to.
You’ll also generally need Form 1099-R to report the distribution or rollover — but if you’re using a standard prototype plan through a major custodian like Fidelity, Vanguard, or Schwab, the custodian issues this form, not you directly. Your job is simply to make sure you actually receive it and pass it along to whoever prepares your taxes, not to generate it yourself.
The Rollover Mistake That Makes the Whole Thing Taxable
If you receive the funds directly as a check rather than doing a direct trustee-to-trustee transfer, you have exactly 60 days to redeposit the full amount into a new qualifying account. Miss that window — even by a single day — and the entire distribution becomes taxable, plus a potential early-withdrawal penalty if you’re under 59½. This is entirely avoidable by insisting on a direct transfer between custodians rather than a personal check, which is the standard, safer way to handle this regardless of which option you choose above.
What This Doesn’t Cover
If your Solo 401(k) has ever been large enough to matter for asset-protection purposes, there’s a real legal nuance worth knowing before you roll everything into an IRA: 401(k) plans generally carry stronger creditor protection under federal law than IRAs do in many states, and that protection can shrink once the money moves. This matters more in high-litigation professions than for most freelancers, but if your account balance is substantial, it’s worth a conversation with a CPA or attorney before defaulting to the simplest rollover option.
Sources: IRS rules on one-participant 401(k) eligibility; Form 5500-EZ instructions and penalty structure; IRS 60-day rollover rule; IRS Form 1099-R instructions.
This article is educational content, not individualized tax or legal advice. Consult a qualified professional about your specific situation.