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Why Choosing a Specialized 401(k) Audit Firm isn’t Optional

If your employee benefit plan requires an audit, choosing the right CPA firm isn’t just a box to check—it’s one of the most important risk decisions you’ll make as a plan sponsor.

Too many companies treat a 401(k) audit like any other financial statement audit. It’s not. And the wrong choice doesn’t just lead to a frustrating experience—it can expose your plan to regulatory scrutiny, penalties, and costly rework.

Let’s break down why specialization matters—and what’s really at stake.

What Makes 401(k) Audits Different?

Employee Benefit Plan (EBP) audits operate under a completely different level of scrutiny than most other audits. They are governed by:

  • ERISA requirements
  • Department of Labor (DOL) oversight
  • AICPA-specific audit standards
  • Unique testing areas like participant data, contributions, and prohibited transactions

This isn’t general audit work. It’s a niche discipline that requires dedicated training, systems, and experience.

And the data backs it up. Firms that perform only a small number of EBP audits have dramatically higher failure rates. In fact, studies have shown deficiency rates as high as 67%–75% for firms performing fewer audits

That’s not a margin of error—that’s a systemic problem.

The Real Risk of Using a Non-Specialist Firm

Many plan sponsors end up with a non-specialist firm for one simple reason: “They already do our taxes or financials—so they offered to do the audit too.”

Sounds convenient. It’s not. Here’s what typically happens:

More of Your Time Gets Burned

Non-specialist firms don’t have streamlined processes. That means:

  • Endless follow-up requests
  • Poorly structured PBC lists
  • Repeated back-and-forth for the same data

👉 What should take <5 hours of your time turns into 15–20+ hours.

Higher Hidden Costs

These firms often:

  • Underestimate the complexity
  • Expand scope mid-audit
  • Bill additional hours to “figure things out”

What started as a “cheap” audit ends up costing more than a specialist firm.

Increased Risk of Errors and Deficiencies

EBP audits require precision in areas like:

  • Employee contributions timing
  • Employer match calculations
  • Eligibility and participant data
  • Party-in-interest transactions

These are exactly the areas where non-specialist firms struggle most. Mistakes here can lead to:

  • DOL scrutiny
  • Rejected Form 5500 filings
  • Required corrections and re-filings

Potential DOL Investigation

The Department of Labor actively reviews EBP audits—especially those from firms more likely to have deficiencies. If your audit is flagged:

  • Workpapers can be requested
  • Your audit quality is reviewed
  • Deficiencies can trigger penalties or corrective action

👉 Even though the audit firm made the mistake—you, as the plan sponsor, deal with the consequences.

Why Some Firms “Dabble” in 401(k) Audits (and Why That’s a Problem)

Most non-specialist firms don’t intentionally take on risk—they just underestimate it. Common reasons:

  • They don’t want to lose the client relationship
  • They assume it’s “just another audit”
  • They lack the volume to justify proper investment in training and systems

The result? They never build the expertise required to do it right. And your audit becomes their learning curve.

The Case for a Specialized 401(k) Audit Firm

Now let’s flip the script.

What you get with a specialist:

✅ Faster, More Efficient Process

  • Standardized workflows
  • Smarter upfront data requests
  • Minimal follow-ups
  • Less disruption to your team

✅ Predictable, Flat Pricing

  • No surprise fees
  • No scope creep
  • No “figuring it out as we go” billing

✅ Full-Population Testing (Not Sampling Shortcuts)

  • Specialist firms leverage advanced methodologies to test entire datasets—not just samples. The result is more accuracy, less risk

✅ Built-In Compliance Expertise

Specialists don’t just audit—they understand:

  • ERISA requirements
  • DOL expectations
  • AICPA standards
  • Plan document nuances

✅ Audit That Holds Up Under Scrutiny

When done right, your audit:

  • Passes peer review
  • Withstands DOL inspection
  • Supports accurate Form 5500 filing

The Bottom Line

A 401(k) audit is not the place to cut corners—or rely on convenience. The difference between a specialist and a non-specialist firm isn’t just experience, it’s:

  • Time saved
  • Cost predictability
  • Audit quality
  • Regulatory risk

And ultimately: Whether your audit protects your plan—or puts it at risk.

What Plan Sponsors Should Do Next

Before engaging a CPA firm for your next audit, ask:

If the answers aren’t clear—or confident—you’re likely not talking to a specialist.

The difference between a specialist and a generalist isn’t subtle—it’s measurable. In time. In cost. And in risk.

Choose accordingly.

Frequently Asked Questions

Why do I need a specialized CPA firm for a 401(k) audit?

A specialized CPA firm has dedicated expertise in ERISA requirements, Department of Labor (DOL) regulations, and employee benefit plan (EBP) audit standards. Unlike general audit firms, specialists use proven processes, full-population testing, and experienced teams to ensure accuracy and compliance—reducing the risk of deficiencies, delays, and regulatory scrutiny.

What are the risks of using a non-specialist firm for a 401(k) audit?

Using a non-specialist firm can lead to higher error rates, inefficient audits, and increased regulatory risk. These firms often lack the training and systems needed for EBP audits, which can result in rejected Form 5500 filings, additional audit costs, and potential DOL investigations. Studies have shown significantly higher deficiency rates among firms that perform only a small number of these audits.

How much time should a 401(k) audit take from a plan sponsor?

With a specialized audit firm, most plan sponsors spend less than 5 hours supporting the audit due to efficient processes and clear upfront data requests. Non-specialist firms often require 10–20+ hours due to repeated follow-ups, disorganized requests, and lack of standardized workflows.

Are cheaper 401(k) audits actually more expensive in the long run?

Often, yes. Lower-cost firms frequently underestimate the complexity of EBP audits, leading to scope creep, additional billing, and longer timelines. When you factor in internal time, inefficiencies, and the risk of corrections or re-filings, a “cheap” audit can end up costing more than a flat-fee audit from a specialized firm.

What makes PriceKubecka different from other 401(k) auditors?
PriceKubecka is among the top 1% of CPA firms nationally by 401(k) audit volume. Three key differentiators: (1) proprietary technology that automates 90% of the audit, (2) a flat-rate fee starting at $12,000 with no surprises, and (3) a comprehensive approach that reviews ALL payroll data rather than just a sample, catching errors other auditors miss.
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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