The October 15 extended Form 5500 filing deadline is just weeks away, but your 401(k) audit isn’t finished—or perhaps it hasn’t even started. If you don’t have a valid extension, your filing may already be late.
The first instinct may be to panic, start forwarding old email chains or upload every document you can find. That usually creates more confusion, not more progress. What you need now is a clear picture of where the filing stands, what’s holding it up, and who’s responsible for moving it forward.
Here’s where to start.
1. Confirm Your Actual Filing Deadline
First, determine whether a valid extension is in place.
A Form 5558 filed by July 31 generally extends the deadline for a calendar-year plan to October 15. For the 2025 plan year, that means October 15, 2026. Do not assume your TPA or recordkeeper filed it. Ask for confirmation and keep a copy with the plan’s records.
If a Form 5558 wasn’t filed, ask your TPA or auditor whether the plan qualifies for an automatic extension tied to the employer’s federal income tax return extension. But keep in mind that this option applies only when specific conditions are met; it’s not guaranteed for every plan.
2. Put One Person in Charge
When an audit is behind, the biggest problem usually isn’t a lack of effort. It’s that the right hand doesn’t know what the left is doing. No one has a complete view of what is happening. Assign one internal person to own the process. That person should know:
- What the auditor is waiting for.
- Who owns each request.
- What’s been sent.
- What are the upcoming audit milestones.
- What could prevent the report from being issued.
At this stage, “I thought someone sent that” is not a good answer.
3. Determine What’s Needed to Start, or Unstick, the Audit
If you haven’t engaged an auditor yet, you need to move immediately—but not so fast that you have to hire whoever picks up the phone first.
Ask potential CPA firms:
- Do you have the capacity to complete the audit within our remaining timeline?
- How much work will be required from our internal team?
- How many employee benefit plan audits does your team perform?
- How familiar are you with our recordkeeper and service providers?
An experienced EBP audit team is more likely to know which reports to request, how to work with the major recordkeeping platforms and how to resolve common issues without sending the sponsor on a scavenger hunt.
If the audit is already underway, ask your auditor to divide the outstanding work into three categories:
Items blocking audit testing. These are the records the team needs before it can perform or complete testing.
Exceptions that require an answer. Discrepancies, missing documents, or possible compliance issues that have already been identified.
Lag time in receiving information. This can be delays in communication from the auditor, or your recordkeeper/TPA/advisor, or from your staff.
Then ask a direct question: “What could stop this audit from being issued?” That answer should determine where your team spends its time first.
4. Bring Known Problems into the Open
If you know about late participant deposits, missing eligibility records, payroll discrepancies, unresolved loans, or other plan errors, tell your auditor now. Don’t wait and hope the issue won’t show up in testing. That move usually costs more time because the auditor must stop, gather the history, and determine whether the matter was corrected and properly reported.
Late deposits are especially important. Employee contributions generally must be deposited as soon as they can reasonably be separated from company assets. When that doesn’t happen, the issue may require lost earnings, additional reporting, and other correction steps.
5. Answer Audit Questions with Evidence, not just Explanations
“We believe this was correct” doesn’t close an audit question. A useful response gives the answer, the supporting record, and any correction made. For example:
The employee became eligible April 1 and entered July 1. Attached is their first day checklist and the email where they were notified of their eligibility.
This answer is much more effective than forwarding a long email chain for the auditor to figure out.
Also avoid sending screenshots with no source, spreadsheets with overwritten formulas, or 20 attachments labeled ‘support.’ Name the files clearly and tell the auditor which questions each document answers. The goal is not to send more. It’s to make the answers easy to verify.
6. Know What Happens if the Filing is Already Late
Missing the deadline can be costly. The DOL may assess up to $2,739 per day for failure to file a complete and accurate Form 5500. Penalties are not automatic, and relief may apply. See the DOL’s Form 5500 filing instructions for details.
If no valid extension applies, the plan may qualify for the Department of Labor’s Delinquent Filer Voluntary Compliance Program. The program allows eligible plan administrators to voluntarily complete late filings and pay reduced civil penalties.
This is another reason not to let an unfinished audit sit. Your advisors can help determine whether the program applies and what steps need to be taken.
7. Fix Next Year While This Year is Still Fresh
Once the audit and filing are complete, hold a short post-audit meeting. Identify the issues that consumed most of the time and turn them into recurring controls.
Also address operational errors before year-end, while the records and circumstances are still fresh. If you wait until next year, you’ll end up spending more time refamiliarizing yourself with the problem than it takes to make the fix today.
If your audit is behind—or hasn’t started yet—there’s still a path forward, but the time to act is now. It takes clear ownership, honest communication and an auditor who knows what information is truly needed.
The priority now is not to make the situation look less serious. It’s to get control of it and keep it from becoming a bigger one.
Frequently Asked Questions
What is the 401(k) audit and Form 5500 filing deadline for 2026?
The extended Form 5500 filing deadline for a calendar-year 401(k) plan is October 15, 2026, provided the plan has a valid extension. The original deadline was July 31, 2026. Plan sponsors should confirm their extension status with their third-party administrator (TPA) or recordkeeper rather than assume one was filed.
Can I still start my 401(k) audit in September and meet the October 15 deadline?
It may still be possible, but the remaining timeline is tight. Contact an experienced employee benefit plan auditor immediately to determine whether the audit can be completed. Ask about the firm’s availability, required documentation, expected workload for your team, and potential issues that could delay completion.
What should I do if my 401(k) audit has not started?
If your required 401(k) audit has not started, confirm your Form 5500 deadline and contact an auditor immediately. Assign one person to coordinate the process, gather required records, and establish a schedule for completing audit testing and resolving outstanding questions. Avoid delaying the engagement while searching for a perfect solution.
What should I do if my 401(k) audit is behind schedule?
Ask your auditor to identify exactly what is preventing completion. Separate outstanding work into three categories: missing records needed for testing, exceptions requiring answers, and delays involving the recordkeeper, TPA, advisor, or internal staff. Assign an owner and deadline to each item, prioritizing anything that could prevent the audit report from being issued.
What happens if my 401(k) audit and Form 5500 filing are already late?
If your filing deadline has passed and no valid extension applies, act promptly to complete the audit and filing. Eligible plan administrators may use the Department of Labor’s Delinquent Filer Voluntary Compliance Program (DFVCP) to voluntarily file overdue reports and pay reduced civil penalties. Eligibility generally requires acting before receiving a DOL notice of failure to file.
Review the DOL’s DFVCP guidelines with your advisors to determine the appropriate next steps.
