Off-Cycle 401(k) Audits: What Non-Calendar-Year Plan Sponsors Should Know

by | Oct 8, 2026

For most 401(k) plan sponsors, audit season centers around the July 31 Form 5500 deadline and the October 15 extended deadline. But not every 401(k) plan operates on a calendar year.

If your 401(k) plan has a fiscal year or other non-calendar-year plan year, your Form 5500—and any required employee benefit plan audit—follows a different schedule. In general, Form 5500 is due by the last day of the seventh month after the plan year ends. A Form 5558 can generally provide an extension of up to 2½ months.

That means 401(k) audit deadlines occur throughout the year, not just during the traditional summer audit season.

At PriceKubecka, we see these off-cycle 401(k) audits as an opportunity. A different plan year can give sponsors more flexibility to prepare, coordinate with service providers and complete the audit without competing with the traditional July and October filing rush.

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The Off-Cycle Advantage: More Time to Focus on the Audit

The audit procedures for a non-calendar-year 401(k) plan are generally the same as those for a calendar-year plan. What changes is the timing.

For example, a plan with a June 30 year-end generally has a Form 5500 deadline of January 31 rather than July 31. With an approved extension, that deadline can generally move another 2½ months.

That different schedule can create some practical advantages:

  • More focused coordination: Your audit may fall outside the busiest period for auditors, recordkeepers, TPAs, and internal finance teams.
  • More time to address issues: Starting early gives your team time to respond to audit questions and resolve exceptions before the filing deadline.
  • Better internal preparation: Payroll, HR and finance teams may have more bandwidth to collect census data, payroll records, and supporting documentation.
  • Less deadline pressure: An audit that starts well before the Form 5500 due date leaves more room for unexpected questions or missing information.

The goal isn’t simply to finish the audit. It’s to complete it efficiently and give your organization enough time to address issues before the filing deadline arrives.

When Is Form 5500 Due for a Fiscal-Year 401(k) Plan?

A non-calendar-year plan does not automatically follow the July 31 or October 15 deadlines associated with calendar-year plans.

The Department of Labor generally requires Form 5500 to be filed by the last day of the seventh calendar month after the end of the plan year. A plan sponsor may generally request a one-time extension of up to 2½ months by filing Form 5558 before the normal filing deadline.

For example:

  • A March 31 plan year-end generally produces an October 31 Form 5500 deadline.
  • A June 30 plan year-end generally produces a January 31 deadline.
  • A September 30 plan year-end generally produces an April 30 deadline.
  • A December 31 plan year-end generally produces the familiar July 31 deadline.

For plan sponsors with an audit requirement, the audit must be completed in time for the auditor’s report to accompany the Form 5500 filing.

When Should You Start an Off-Cycle 401(k) Audit?

Don’t use the filing deadline as the date to begin thinking about the audit. Work backward from it.

Your auditor may need time to review participant census data, payroll information, contributions, eligibility, distributions, participant loans, plan documents and recordkeeper reports. If testing uncovers an exception or missing information, your team will also need time to investigate and respond.

For a fiscal-year 401(k) plan, the better question is: How early do we need to begin the audit so there is enough time to finish testing and resolve issues before our Form 5500 deadline?

That timeline will vary by plan, but earlier coordination usually gives the sponsor more control over the process.

Financial Clarity With Flat-Fee 401(k) Audit Pricing

Budgeting for an employee benefit plan audit shouldn’t be unpredictable.

PriceKubecka uses a flat-fee pricing structure so plan sponsors know the audit fee before the engagement begins rather than waiting to see how many hours are ultimately billed.

For organizations with non-calendar-year plans, that makes the audit easier to incorporate into the organization’s annual compliance and budgeting calendar.

Why Year-Round 401(k) Auditing Matters

A 401(k) plan with a March, June or September year-end shouldn’t have to structure its audit around another company’s traditional audit season.

PriceKubecka’s employee benefit plan audit practice operates throughout the year. Our auditors specialize in 401(k), 403(b) and ESOP plan audits, allowing us to serve plan sponsors whose deadlines fall in virtually any month.

Year-round availability provides three practical benefits:

  1. Continuity of expertise. Your engagement is handled by an audit team focused on employee benefit plans.
  2. Audit timing built around your plan year. You don’t have to wait for the traditional calendar-year audit cycle.
  3. Consistent processes. Our audit process is designed specifically around employee benefit plan testing and documentation.

If your 401(k) plan operates on a fiscal year, your auditor should be prepared to do the same.

Use Your Fiscal-Year Timing to Catch Problems Earlier

An off-cycle audit can also give sponsors an opportunity to identify problems before they become filing problems. Common issues uncovered during 401(k) audits include:

Finding these issues earlier can give the plan sponsor, TPA, and other service providers more time to determine whether corrections or additional documentation are needed.

Don’t Assume October 15 Is Your Deadline

October 15 gets most of the attention because it is the extended Form 5500 deadline for many calendar-year plans. But if your 401(k) plan year ends on a different date, October 15 may have nothing to do with your filing calendar.

Your audit schedule should start with three questions:

When does our plan year end?
When is our Form 5500 actually due?
How much time does our auditor need to complete the audit before that date?

Once those dates are clear, you can build the audit around your organization’s timeline instead of the traditional 401(k) audit season.

Need a 401(k) Auditor for a Non-Calendar-Year Plan?

PriceKubecka performs employee benefit plan audits year-round for organizations with both calendar-year and fiscal-year 401(k) plans.

Our team works with plan sponsors across the country to complete 401(k) audits efficiently, coordinate with recordkeepers and TPAs, and keep the audit moving toward the plan’s specific Form 5500 deadline.

Your plan year may be different. Your audit process should be built around it.

Frequently Asked Questions

When is Form 5500 due for a non-calendar-year 401(k) plan?

Form 5500 is generally due by the last day of the seventh calendar month after the plan year ends. For example, a 401(k) plan with a June 30 year-end generally has a January 31 Form 5500 deadline. An extension of up to 2½ months may generally be requested using Form 5558.

Does a fiscal-year 401(k) plan still need an audit?

Potentially. Having a non-calendar-year plan does not eliminate the employee benefit plan audit requirement. Whether an audit is required depends on the plan’s filing status and applicable participant-count rules, not simply whether the plan ends on December 31.

When should a non-calendar-year 401(k) audit begin?

A plan sponsor should begin the audit early enough to complete testing, answer auditor questions and resolve exceptions before the Form 5500 filing deadline. Because the filing deadline is based on the plan-year end, a fiscal-year 401(k) audit may need to begin at a completely different time of year than a traditional calendar-year audit.

Can we change 401(k) auditors for an off-cycle or fiscal-year plan?

Yes. A plan sponsor can change audit firms even when its plan operates on a non-calendar year. The new auditor will generally need information from the sponsor and may communicate with the predecessor auditor as part of the transition. Starting the process early makes it easier to complete the change before the filing deadline.

Are off-cycle 401(k) audits different from regular 401(k) audits?

The core audit procedures are generally the same. The primary difference is timing. A non-calendar-year plan has its own plan-year end and Form 5500 filing deadline, so the audit should be scheduled around that deadline rather than the traditional July 31 and October 15 calendar-year filing dates.

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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