Late Deposits: The Most Common (and Costly) 401k Error

by | Apr 29, 2026

As 401(k) audits ramp up across the country, plan sponsors have a critical opportunity to address common compliance issues before they turn into audit findings. Based on hundreds of audits performed by PriceKubecka, one issue consistently rises to the top.👉Late 401(k) deposits.

What Is a Late 401(k) Deposit?

When employees defer part of their paycheck into a 401(k), those funds must be deposited into the plan as soon as administratively possible.

Yes, there’s a rule about the 15th business day of the following month—but here’s what most plan sponsors miss: That’s NOT a safe harbor. It’s the absolute maximum deadline.

The real standard is: Deposit contributions as soon as you reasonably can.

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Why This Trips Up Plan Sponsors

Let’s say you typically deposit contributions 3 days after payroll. That becomes your benchmark.

So if the next deposit happens 10 days after payroll… That’s a late deposit—even if it’s before the 15th business day.

This is where most companies get flagged in audits.

What Happens If You Have Late Deposits?

If your auditor identifies late deposits, you’re required to:

  1. Calculate Lost Earnings – Determine how much participants missed out on because their money wasn’t invested.
  1. Make Participants Whole – You must fund the difference. This is your correction (penalty).
  1. Report It – Late deposits are disclosed in:

👉 And yes, this gets the attention of the Department of Labor (DOL).

When Late Deposits Become a Bigger Problem

Occasional delays happen. But repeated late deposits? That’s a pattern—and a red flag. Unchecked, this can:

  • Trigger DOL scrutiny
  • Lead to expanded investigations
  • Create ongoing compliance risk

How to Fix Late Deposits (For Good)

The solution is simple but it requires discipline.

1. Make 401(k) deposits part of payroll

Treat them like payroll taxes. Same day. No exceptions.

2. Establish a consistent timeline

Whatever your “as soon as possible” timeline is—stick to it.

3. Build redundancy into the process

  • Train a backup processor
  • Ensure coverage during PTO or turnover

4. Document everything

If a delay happens, it’s vital to record why it occured and what corrective action was taken.

5. Align systems and providers

Work with your payroll provider and recordkeeper to:

  • Define your earliest deposit timing
  • Ensure systems support it

Bottom Line

Late deposits aren’t complicated—but they are high-risk and highly visible.

The good news? They’re also one of the easiest audit findings to eliminate entirely.

Work With a 401(k) Audit Specialist

If late deposits showed up in your audit—or you want to make sure they don’t next year—PriceKubecka can help. We specialize in streamlined, flat-fee 401(k) audits that:

👉 Let’s make next year’s audit your easiest one yet.

Frequently Asked Questions

What is considered a late 401(k) deposit?

A late 401(k) deposit occurs when employee deferrals are not deposited into the plan as soon as administratively possible, even if they are deposited before the 15th business day of the following month.

Is the 15th business day rule a safe harbor for 401(k) deposits?

No. The 15th business day is the maximum deadline, not a safe harbor. Employers must deposit contributions as quickly as they reasonably can, often within a few days of payroll.

How do you correct late 401(k) deposits?

To correct late deposits, plan sponsors must:

  • Calculate lost earnings for participants
  • Deposit those earnings into participant accounts
  • Report the issue on Form 5500 and audit disclosures
Can late 401(k) deposits trigger a DOL audit?

Yes. Repeated or significant late deposits can attract attention from the Department of Labor (DOL) and may lead to further investigation or penalties.

How can employers prevent late 401(k) deposits?

Employers can prevent late deposits by:

  • Depositing contributions at the same time as payroll
  • Creating a consistent, documented process
  • Training backup personnel
  • Coordinating with payroll providers and recordkeepers

Frequently Asked Questions

What should I do if I missed the October 15 Form 5500 deadline?

First, confirm that October 15 was actually your plan’s deadline and that a valid extension applied. If the deadline has passed, determine what is preventing the Form 5500 from being completed. If a required 401(k) audit is unfinished or hasn’t started, contact an experienced employee benefit plan auditor immediately and work with your other advisors to determine the appropriate filing and penalty-relief options.

Can you file Form 5500 after the deadline?

Yes. A delinquent Form 5500 can still be filed after its due date. Filing late does not eliminate the filing requirement, however, and potential DOL and IRS penalties may apply. Eligible plan administrators may be able to use the DOL’s Delinquent Filer Voluntary Compliance Program to reduce certain penalties.

What are the penalties for filing Form 5500 late?

The Department of Labor may assess substantial civil penalties for failure to file a complete and accurate Form 5500. Current Form 5500 instructions state a potential DOL penalty of up to $2,739 per day. The IRS can separately assess $250 per day, up to $150,000 per plan year, for certain late Form 5500-series filings. Actual penalties and available relief depend on the circumstances.

What is the DOL's Delinquent Filer Voluntary Compliance Program?

The DFVCP is a Department of Labor program that allows qualifying plan administrators to voluntarily submit delinquent Form 5500 filings and pay reduced civil penalties. Eligibility generally requires correcting the filing before the DOL has provided written notice of the failure to file.

What if my 401(k) audit hasn't started and the Form 5500 deadline has already passed?

If your plan is required to have an independent audit, missing the Form 5500 deadline does not remove that requirement. Contact an employee benefit plan auditor as soon as possible, explain that the filing is already late and determine what records are needed to begin the audit immediately. Work simultaneously with your TPA and other advisors to address the delinquent filing and determine whether penalty-relief options are available.

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