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.

Does a Fiscal-Year 401(k) Plan Still Need an Audit?

Potentially, yes.

Operating on a fiscal year does not eliminate or change the basic requirement for an independent employee benefit plan audit. Whether a defined contribution plan requires an audit generally depends on its Form 5500 filing status and the applicable participant-count rules—not whether its plan year ends December 31.

For defined contribution plans, the relevant participant count now focuses on participants and beneficiaries who have account balances at the beginning of the plan year, rather than everyone merely eligible to participate.

So an off-cycle plan sponsor should answer two separate questions:

Do we have an audit requirement?

And, if so:

When must that audit be completed so our Form 5500 can be filed on time?

Those are related questions, but they aren’t the same question.

When Should a Fiscal-Year 401(k) Audit Start?

The Form 5500 deadline should be the end of your audit timeline—not the beginning of it. The safest approach is to work backward from your actual filing deadline and establish the audit schedule well in advance.

If an independent audit is required, the auditor’s report generally accompanies the Form 5500 filing. That means the audit needs to be substantially complete before your filing deadline arrives.

There isn’t one audit-start date that works for every plan. The amount of time needed depends on factors such as plan size, the availability of records, the complexity of the plan and whether testing identifies issues requiring follow-up.

A practical timeline should allow time for:

Data collection: Your team may need to gather census information, payroll data, contribution records, recordkeeper reports, participant files and plan documents.

Audit testing: Your auditor will perform required procedures and may select participants or transactions for additional documentation.

Follow-up questions: Missing information and discrepancies often require responses from HR, payroll, the recordkeeper, TPA or other providers.

Resolving exceptions: Eligibility errors, contribution discrepancies, participant loans, distributions, compensation issues and other findings can require additional investigation.

Final review and issuance: The audit team still needs time to complete its review and issue the auditor’s report before the Form 5500 is finalized.

Example: A 401(k) Plan With a March 31 Year-End

Suppose your plan year ends March 31.

Your normal Form 5500 deadline is generally October 31.

With a timely Form 5558 extension, the deadline can generally be extended to January 15.

That does not mean January should become your target date for beginning the audit.

Instead, the plan sponsor and auditor should establish a timeline that leaves enough time before the applicable deadline to obtain records, complete testing and address any unexpected issues.

In other words:

March 31 plan year-end → October 31 normal deadline → January 15 extended deadline

Your audit calendar should be built backward from whichever filing deadline applies.

Example: A 401(k) Plan With a June 30 Year-End

A June 30 plan operates on a very different schedule.

Its Form 5500 would generally be due January 31 of the following year.

With a timely Form 5558 extension, the deadline would generally move to April 15.

For that employer, traditional summer 401(k) “audit season” may be largely irrelevant. Its audit preparation and testing may instead take place during the fall and winter.

That is why a plan with a non-calendar-year end should work with an auditor that maintains employee benefit plan audit capabilities throughout the year.

What Can Delay an Off-Cycle 401(k) Audit?

Having a different deadline doesn’t protect a plan from the same issues that slow down calendar-year audits.

Some common audit roadblocks include:

  • Missing or inaccurate census information
  • Eligibility and plan entry-date errors
  • Incorrect employer contribution or match calculations
  • Incorrect application of the plan’s compensation definition
  • Late participant contributions
  • Participant loan problems
  • Vesting or forfeiture discrepancies
  • Distribution documentation issues
  • Differences between payroll and recordkeeper data
  • Delays obtaining information from outside service providers

One of the advantages of starting early is having time to resolve those issues before they become filing-deadline problems.

What If Your Fiscal-Year Form 5500 Deadline Falls on a Weekend or Holiday?

There is an important exception to the dates in the chart.

If a Form 5500 filing deadline falls on a Saturday, Sunday or federal holiday, the filing can generally be made on the next day that is not a Saturday, Sunday or federal holiday. U.S. Department of Labor

That means sponsors should verify the precise deadline for the applicable filing year rather than relying solely on a recurring calendar.

The month-by-month chart is best used as a planning guide.

What About Short Plan Years?

A short plan year can occur when, for example, a plan changes its plan-year end or terminates and completes the distribution of plan assets.

The general Form 5500 timing rule still applies: the filing is generally due by the last day of the seventh calendar month after the short plan year ends, subject to an authorized extension. U.S. Department of Labor

Short plan years can introduce additional reporting and audit considerations, so sponsors should coordinate the filing timeline with their TPA, auditor and other advisors rather than assuming the normal annual schedule applies.

Don’t Build Your Audit Around October 15 If October 15 Isn’t Your Deadline

October 15 gets enormous attention in the 401(k) industry because it is the extended Form 5500 deadline for many calendar-year plans.

But it’s only one deadline.

For a non-calendar-year plan, your filing date could fall in January, April, June, November—or virtually any other month.

Your audit calendar should therefore begin with three questions:

When does our 401(k) plan year end?

When is our Form 5500 due?

When does the audit need to begin to comfortably meet that deadline?

Once those dates are established, your organization can build a recurring compliance calendar around its own plan rather than someone else’s audit season.

Looking for a 401(k) Auditor for a Fiscal-Year Plan?

PriceKubecka performs employee benefit plan audits throughout the year for both calendar-year and non-calendar-year 401(k) plans.

Our employee benefit plan specialists perform more than 400 EBP audits annually, including 401(k), 403(b) and ESOP audits. Because employee benefit plan auditing is a significant part of our audit practice, we can work with plan sponsors whose audit and Form 5500 deadlines fall throughout the year.

Whether your plan ends March 31, June 30, September 30 or another date, your audit should be built around your plan year and your deadline.

[Talk to a 401(k) Auditor]

Example: A 401(k) Plan With a March 31 Year-End

Suppose your plan year ends March 31. Your normal Form 5500 deadline is generally October 31.

With a timely Form 5558 extension, the deadline can generally be extended to January 15.

That does not mean January should become your target date for beginning the audit.

Instead, the plan sponsor and auditor should establish a timeline that leaves enough time before the applicable deadline to obtain records, complete testing and address any unexpected issues.

In other words:

March 31 plan year-end → October 31 normal deadline → January 15 extended deadline

Example: A 401(k) Plan With a June 30 Year-End

A June 30 plan operates on a very different schedule.

This plan’s Form 5500 would generally be due January 31 of the following year. With a timely Form 5558 extension, the deadline would generally move to April 15.

For that employer, traditional summer 401(k) “audit season” may be largely irrelevant. Its audit prep and testing may instead take place during the fall and winter.

That’s why a plan with a non-calendar-year end should work with an auditor that maintains EBP audit capabilities throughout the year.

In other words:

June 30 plan year-end → January 31 normal deadline → April 15 extended deadline

What Can Delay an Off-Cycle 401(k) Audit?

Having a different deadline doesn’t protect a plan from the same issues that slow down calendar-year audits. Some common audit roadblocks include:

  • Missing or inaccurate census information
  • Eligibility and plan entry-date errors
  • Incorrect employer contribution or match calculations
  • Incorrect application of the plan’s compensation definition
  • Late participant contributions
  • Participant loan problems
  • Vesting or forfeiture discrepancies
  • Distribution documentation issues
  • Differences between payroll and recordkeeper data
  • Delays obtaining information from outside service providers

One of the advantages of starting early is having time to resolve those issues before they become filing-deadline problems.

What If Your Fiscal-Year Form 5500 Deadline Falls on a Weekend or Holiday?

There is an important exception to the dates in the chart. If a Form 5500 filing deadline falls on a Saturday, Sunday or federal holiday, the filing can generally be made on the next day that is not a Saturday, Sunday, or federal holiday. 

That means sponsors should verify the precise deadline for the applicable filing year rather than relying solely on a recurring calendar. The month-by-month chart is best used as a planning guide.

What About Short Plan Years?

A short plan year can occur when, for example, a plan changes its plan-year end or terminates and completes the distribution of plan assets.

In this case, the general Form 5500 timing rule still applies: the filing is generally due by the last day of the seventh calendar month after the short plan year ends, subject to an authorized extension. 

Short plan years can introduce additional reporting and audit considerations, so sponsors should coordinate the filing timeline with their TPA, auditor, and other advisors rather than assuming the normal annual schedule applies.

Don’t Build Your Audit Around October 15 if it isn’t Your Deadline

October 15 gets enormous attention in the 401(k) industry because it is the extended Form 5500 deadline for many calendar-year plans. But it’s only one deadline.

For a non-calendar-year plan, your filing date could fall in January, April, June, November—or virtually any other month. Your audit calendar should therefore begin with three questions:

  1. When does our 401(k) plan year end?
  2. When is our Form 5500 due?
  3. When does the audit need to begin to comfortably meet that deadline?

Once those dates are established, your organization can build a recurring compliance calendar around its own plan rather than someone else’s audit season.

Looking for a 401(k) Auditor for a Fiscal-Year Plan?

PriceKubecka performs employee benefit plan audits throughout the year for both calendar-year and non-calendar-year 401(k) plans.

Our EBP specialists perform more than 400 audits annually, including 401(k), 403(b) and ESOP audits. Because employee benefit plan auditing is a significant part of our audit practice, we can work with plan sponsors whose audit and Form 5500 deadlines fall throughout the year.

Whether your plan ends March 31, June 30, September 30, or another date, your audit should be built around your plan year and your deadline.

[Talk to a 401(k) Auditor]

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