How Payroll Codes Can Create 401(k) Compliance Issues
Published on by Jessica Doremus in Benefit Plan Audits
- Payroll code errors can create significant 401(k) compliance issues when payroll systems and plan documents use different definitions of eligible compensation.
- Misalignments can build over time and affect multiple areas of a plan, including employee deferrals, employer matching contributions, compliance testing, and participant accounts.
- Errors can lead to costly corrections and increased audit or IRS exposure, particularly when they repeat across multiple payroll cycles or go undetected for years.
- Regular payroll code reviews and strong change management controls can help reduce compliance risk by keeping payroll coding aligned with plan provisions.
When plan sponsors think about fiduciary risk, the conversation usually turns to investment performance, plan fees, or compliance testing. Those are important, but some of the most costly and persistent errors in 401(k) plan administration have nothing to do with any of them.
They are buried in payroll codes, quietly compounding with every pay cycle. If your payroll system and plan document aren’t in sync, your plan isn’t operating correctly, and you may not know it until the damage is already done.
How payroll codes affect plan compliance
Every payroll system runs on pay codes: salary, overtime, bonuses, commissions, auto allowances, fringe benefits, and more. Your plan document defines what types of compensation are eligible for employee deferrals, employer matching contributions, nonelective contributions, and compliance testing.
When those two frameworks fall out of alignment, the plan fails to operate according to its written terms – a requirement under ERISA. This is one of the most common operational failures auditors encounter in 401(k) plans, and the correction costs can be significant.
Where payroll code errors begin
Payroll code misalignments rarely happen all at once. They tend to accumulate gradually, often stemming from:
- New pay codes added without review: HR or payroll introduces a new code, such as a retention bonus, a car allowance, a tax gross-up, without evaluating whether it qualifies as eligible compensation under the plan document.
- Legacy coding that was never validated: Many plans inherit payroll setups built years ago that were never reconciled to the plan document or were simply wrong from the start.
- Mismatches between deferral and match eligibility: A pay code might be correctly included for deferrals but incorrectly excluded from employer match calculations, or vice versa.
- Nuanced pay types that fall through the cracks: Auto allowances, fringe benefits, certain bonuses, and other types of compensation are subject to specific IRS rules (such as Treasury Reg. Section 1.414(s)-1) and are frequently misclassified.
The cost of payroll code errors
Payroll code errors repeat every payroll cycle, affect every participant paid under the impacted code, and can go undetected for years. The consequences include:
- Missed deferrals: The plan must fund a Qualified Nonelective Contribution (QNEC) plus lost earnings for affected participants.
- Missed employer match contributions: The employer must make corrective contributions, often with lost earnings added on top.
- Ineligible contributions: Contributions must be refunded or reallocated and earnings adjusted, generating complex and sensitive participant communications.
- Compliance testing distortions: Incorrect compensation definitions can skew ADP/ACP testing, 415 limits, and top-heavy calculations.
- Audit and IRS exposure: Auditors routinely test payroll mapping, and errors are a significant red flag. Issues may need to be disclosed in the audit report and corrected under EPCRS. Repeated failures may be viewed as systemic noncompliance.
See the IRS 401(k) Fix-It Guide to determine the scope of required corrections.
Building a stronger governance process
Payroll code risk is entirely manageable with the right oversight structure. Plan sponsors should implement a formal governance process that includes:
- An initial payroll code audit: Inventory all pay codes and map each one to the plan document’s definitions for deferral eligibility, match eligibility, and testing compensation.
- Annual reviews: Reconcile payroll codes to the plan document at least once per year and confirm no changes were made outside of a formal review process.
- Change management controls: Require a review against plan provisions before any new pay code is added or modified, and document the determination.
- Documentation and sign-off: Maintain a payroll code mapping file and establish a periodic sign-off process involving both HR/payroll and plan fiduciaries.
- Coordination with your recordkeeper and advisor: Ensure payroll coding aligns with recordkeeper data feeds and that contribution calculations reflect the intended compensation definitions.
Start with a payroll code review
If your organization hasn’t recently reconciled its payroll codes to your plan document, now is the time. The process doesn’t have to be overwhelming, but it does need to happen, and it needs to be documented. Our team of top employee benefit plan pros can help you prepare for your audit and identify potential issues. Contact us today for a free consultation.
Additional resources
Looking for more ways to prepare for your next employee benefit plan audit? Our 401(k) plan management benchmarking report provides insights into how organizations are managing their plans, and our employee benefit plan audit FAQ answers common questions about the audit process.
You can also explore our extensive library of employee benefit plan audit resources. As always, we’re here to help.
