Late deferral deposits are the single most common ERISA error employers run into, and they are also the easiest one to trip over without noticing. Every payroll cycle, an employer withholds employee salary deferrals and loan repayments from paychecks. From the moment that money is withheld, it is no longer company money — it is plan assets held in trust for participants. If it sits in the operating account a few days too long, the plan has a fiduciary breach on its hands, and it is the employer, not the recordkeeper, who owns the problem.
This guide is written for plan sponsors: how the rule actually works, how to find late deposits in your own records, the correction path, what gets reported on the Form 5500, and the controls that stop it from recurring.
Why deferral timing is a fiduciary issue, not a payroll issue
Withheld deferrals become plan assets. Holding them in the employer’s general account — even unintentionally, even for a few days — commingles plan assets with company assets and costs participants investment earnings. The Department of Labor treats that as a prohibited transaction and a breach of fiduciary duty, which is why it is one of the first items an investigator asks about.
The people exposed are the plan’s fiduciaries: the company as plan sponsor, the 402(a) named fiduciary, and whoever controls deposit timing. Payroll may be the mechanic, but liability sits at the fiduciary level — delegating payroll processing to a vendor does not delegate the fiduciary duty for deposit timing.
What the deposit deadline actually says
The rule is often misremembered as a fixed number of days. It is not. The DOL standard: participant contributions must be deposited as of the earliest date on which they can reasonably be segregated from the employer’s general assets. There is an outer limit tied to the month following withholding, but it is a backstop — not a safe harbor.
In practice the DOL judges you against your own demonstrated capability. If your records show you usually funded the plan two business days after payroll, a period funded on day fifteen is late even though it fell inside the outer limit. Your routine deposit speed becomes your standard.
A separate safe harbor exists for small plans, under which deposits made within a short window after withholding are deemed timely. Larger plans have no equivalent shortcut, so once you cross the participant-count threshold that triggers the audit requirement, deposit timing deserves a hard look.
Items subject to the same timing discipline
- Pre-tax and Roth salary deferrals
- After-tax employee contributions
- Participant loan repayments withheld from pay
- Deferrals from off-cycle payrolls: bonuses, commissions, final paychecks, corrected payrolls
Employer contributions — match, profit sharing, safe harbor — follow a different funding deadline and are not part of this rule.
How to find late deposits in your own records
You do not need an auditor for this check. Pull two data sets and compare them line by line.
- Payroll register by pay date for the plan year, showing withheld deferrals and loan repayments per pay period.
- Trust or recordkeeper contribution report showing the date each contribution was received and allocated.
The comparison, step by step
- Line up every pay date with its matching deposit date.
- Calculate the business-day gap for each pair.
- Find your normal gap — the figure you hit in most pay periods.
- Flag every pay period whose gap exceeds that normal figure.
- Confirm deposited dollars match withheld dollars; a partial deposit is a late deposit for the unfunded portion.
- Check off-cycle payrolls separately. They are where most late deposits hide, because they skip the routine.
- Document what you found, and why any outlier happened, while the reason is knowable.
Bank holidays, a payroll provider conversion, and the week the payroll administrator was out are the usual culprits. None excuse a late deposit, but a written explanation beats a shrug two years later during an annual plan audit.
The correction path
Correction has three parts, and the order matters.
1. Deposit the principal immediately
Fund the withheld amount to the plan and allocate it to the affected participant accounts. Do not wait for the rest of the analysis to finish.
2. Calculate and fund lost earnings
Participants are made whole for earnings missed while the money was out of the plan. Lost earnings run from the date each deposit should have been made to the date it was, and the employer — not the plan — pays them.
3. Complete the formal correction
The DOL’s Voluntary Fiduciary Correction Program is the route sponsors typically use to formally resolve the breach and close the exposure. There is also an excise tax dimension to the prohibited transaction, which is why late deposits get reviewed by both your TPA and your CPA. Work the filing package with your 3(16) plan administrator and ERISA counsel — the mechanics are procedural but unforgiving about detail.
What gets reported — and why the report is not optional
The Form 5500 asks directly whether there was a failure to transmit participant contributions on a timely basis. Answering yes puts the amount on the schedule and, for audited plans, into the auditor’s report.
Sponsors are sometimes tempted to answer no because the deposit was “only a few days late” or because it was corrected. Both instincts are wrong. A knowingly inaccurate answer on a signed return is far more serious than a disclosed, corrected late deposit — and the person signing owns it (see who signs the Form 5500). Disclosed-and-corrected is a routine finding; undisclosed is a credibility problem that colors everything else an investigator looks at.
Seven controls that prevent late deposits
- Write down the standard. Put your funding target in a short written procedure — for example, deferrals are transmitted the same business day payroll funds. A documented standard is what makes an outlier visible.
- Make funding part of closing payroll. The deposit should be a step inside the payroll checklist, not a separate task someone remembers later.
- Name a backup. Most late deposits happen when one person is out. A named backup with actual system access solves most of it.
- Cover off-cycle payrolls explicitly. The procedure should say what happens for bonus runs, commissions, and final checks.
- Reconcile monthly, not annually. A monthly payroll-to-trust reconciliation catches a problem while the facts are fresh and the correction is small.
- Review timing at every committee meeting. Put a one-line deposit-timing report in the standing agenda so the record shows fiduciary oversight, not just operations.
- Re-test after any change. New payroll provider, new recordkeeper, an acquisition, a pay-frequency change — each deserves a fresh check of the first few cycles.
Where sponsors get the most exposure
Late deposits rarely arrive as one dramatic failure. They accumulate: a gap in one quarter, a missed bonus payroll, a conversion month where nobody reconciled. By the time the DOL asks, the sponsor is reconstructing years of payroll files and lost-earnings math under time pressure.
That points at the real fix. This is not a payroll accuracy problem; it is a fiduciary monitoring problem. Someone has to own the question “were deferrals deposited on time this month?” and answer it in writing. If nobody owns it, it goes unanswered until it is expensive — a plan review shows whether that ownership actually exists at your organization or only in theory.
Where Admin316 fits
Admin316 works as an outsourced 3(16) plan administrator: contribution monitoring, notice and deadline management, Form 5500 preparation support, and the documentation that makes an audit routine. We treat deposit timing as a monitored item with a monthly answer, not an annual surprise.
The part most providers won’t do is the part that matters most to fiduciary exposure: Admin316 accepts the ERISA 402(a) named-fiduciary appointment. Most 401(k) providers and administrators decline that role and leave the employer standing alone in it. If you want to understand the difference between the fiduciary layers before you decide what to delegate, start with 3(16) vs. 3(21) vs. 3(38) vs. 402(a) and our 402(a) fiduciary services, or read why employers choose Admin316.
If you suspect you have late deferral deposits — or you simply cannot say for certain that you don’t — that uncertainty is the finding. Schedule a call with Admin316 and we will walk your payroll-to-trust timing with you and tell you plainly where you stand.
