Two Months until the 401(k) Filing Deadline, and You Haven’t Started Yet?

by | Aug 13, 2025

If you’re a 401(k) plan sponsor and it’s August, the October 15 Form 5500 deadline is already looming. Normally, I’d be telling you to make sure your auditor is wrapping up fieldwork by now.

But some of you reading this haven’t even found an auditor yet. Maybe you thought your TPA handled it. Maybe you didn’t find out until recently your plan crossed the threshold. Or maybe an engagement letter’s still sitting unsigned in your inbox.

Whatever the reason, here’s the hard truth: If you haven’t already started working with a 401(k) auditor, the clock is already working against you.

The “Normal” 401(k) Audit Timeline

For a large plan audit done right:

  • May–June: Engagement letter signed, document requests sent.
  • July–August: Fieldwork testing.
  • September: Draft financial statements issued, reviewed, finalized.
  • Early October: Final audit report delivered, Form 5500 filed.

The “It’s August and We Don’t Have a 401(k) Auditor Yet” Timeline

If you’re starting in mid-August, here’s what your reality looks like:

Man working on phone

Week 1 (This Week):

  • Identify and hire an ERISA-experienced auditor immediately.
  • Sign the engagement letter within 24–48 hours.
  • Send all required documents within days, not weeks.

Week 2–3:

  • Auditor begins fieldwork at a sprint—no long pauses, no “we’ll get to it.”
  • Expect daily document requests; respond same-day.

Late August–Early September:

  • Fieldwork wraps up if everyone’s moving fast.
  • Draft financial statements issued ASAP.
  • TPA starts finalizing the Form 5500.

Mid–Late September:

  • Resolve all findings, corrections, and questions quickly.
  • Final audit report delivered.

Early October:

  • Sign off, file Form 5500 before October 15.

This schedule leaves zero margin for error. A single delay can push you past the deadline.

What Happens if You Miss October 15?

The IRS penalty is $25/day (up to $15,000). The DOL penalty is $2,529/day with no cap. These aren’t theoretical, they are enforced.

What You Need to Do Right Now

If you don’t have an auditor:

But here’s some good news: despite starting so late, you shouldn’t be forced into paying outrageous rush fees or inflated “emergency” pricing. There are firms like PriceKubecka that can start your audit today and still have you filed well before the October 15 deadline.

Our fully automated audit process means we can work fast—without cutting corners—while offering a fixed flat fee well below the national average. Even this late in the game, your audit shouldn’t cost more than $15,000.

401(k) Audit Bottom Line

If you’re still auditor-shopping in August, you’re on a crash-course timeline. It’s doable, but only if you act right now. Every day you wait shaves off precious audit time, and October 15 isn’t moving for you.

But acting now doesn’t have to mean overpaying. PriceKubecka has the capacity to start immediately, leverage technology to get you across the finish line, and charge a flat, reasonable fee. Don’t settle for panic pricing when you can get an on-time, compliant, and cost-efficient 401(k) audit starting today. Please CONTACT US  to get started. 

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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