A per-pay-period match error occurs when payroll calculates the employer match one paycheck at a time while the plan document says the match is determined on an annual basis, or the reverse. The two methods produce different dollars for anyone whose deferrals are uneven across the year, and the gap is an operational failure the sponsor must find and correct, not a rounding issue.
Why a Per-Pay-Period Mismatch Is a Fiduciary Problem
The plan document controls how the match is computed. Payroll and the recordkeeper only implement what they are told. When the implementation drifts from the document, the plan is not being operated according to its written terms, which is a core fiduciary duty. This is a close cousin of the problems we describe in our guide to document, operations and notices mismatches, but it is distinct from a simple match true-up error, because the mismatch is built into the calculation logic itself.
1. Why the two methods diverge
A per-payroll match looks only at the deferral and pay in that single period. An annual match looks at total deferrals and total eligible compensation for the whole plan year. A participant who front-loads deferrals, defers only a few periods, hits an annual limit early, or takes a bonus late in the year can receive very different match amounts under each method.
2. Who gets hurt
Under a per-payroll calculation applied to an annual-match plan, participants with uneven deferral patterns are often shorted because the match stops or shrinks once they cap out. Others may receive more than the document allows. Both outcomes are failures to follow the plan terms.
3. Why it hides for so long
Matching deposits usually arrive on schedule and look plausible. Nobody notices until a participant questions a statement, an auditor reperforms the formula, or a payroll change surfaces the old logic.
How the Mismatch Usually Gets Introduced
- A payroll or recordkeeper conversion where match rules were mapped from a template rather than the document (see payroll provider changes).
- A plan amendment that changed the match formula but never reached the payroll setup.
- A true-up feature that was documented but never switched on.
- A restated document whose match language differs from the prior version and was not compared to operations.
- Different match rules for different employee groups that were collapsed into one payroll code.
Step One: Confirm What the Document Actually Requires
Before anyone recalculates a dollar, settle the governing standard. The answer lives in the plan document, any adoption agreement elections, and every amendment, not in payroll settings or what people remember.
1. Read the match formula and the period it uses
Find the language that defines the matching period: each payroll period, each month or quarter, or the plan year. Note whether a true-up is required or optional, and whether the match is discretionary or formula-based.
2. Read the compensation definition
The match is tied to eligible compensation. If bonuses or other pay are included or excluded, that interacts with the period issue. Our post on the 401(k) compensation definition error covers that overlap.
3. Check eligibility, last-day and allocation conditions
An annual match may carry conditions such as a last-day or hours requirement. Confirm whether those apply, because they decide who is actually owed a make-up.
4. Check whether a safe harbor is involved
If the plan is a safe harbor design, the match formula and timing rules are fixed commitments. See our discussion of safe harbor sponsor commitments before assuming any flexibility.
Step Two: Rebuild the Match From the Document, Not From Payroll
Ask the recordkeeper and payroll provider for participant-level data for each affected plan year, then recompute the match under the standard the document requires.
1. Pull complete deferral and compensation history
You need every pay period’s deferrals, eligible compensation, hire and rehire dates, and the match actually deposited. Population lists should come from the recordkeeper roster, including terminated participants with balances, not just active payroll. Our guide to participant data reconciliation explains how to tie these sources together.
2. Recompute under the correct method
Calculate what each participant should have received, then compare it to what was deposited. Document the formula, the data sources and who reviewed the result.
3. Sort participants into shorted, overpaid and correct
Each group is handled differently. Keep the workpapers organized by plan year so the correction can be explained to an auditor or examiner.
Step Three: Choose the Correction Path
The right fix depends on the document, the size of the failure and whether it is an operational error or a document error. Confirm the current rules with your document provider and legal counsel.
1. Shorted participants
Participants who were owed more generally receive a corrective contribution that restores the missed match, with lost earnings added so they are made whole. Review administrative error correction for the framework.
2. Overpaid participants
Excess match is an operational failure that must also be addressed under the applicable correction program. How an overpayment is handled, including whether it can be reallocated, depends on the plan terms and the correction method used.
3. When the document is the problem
Sometimes the plan sponsor wants the per-payroll method that payroll has been running. A prospective amendment can align the document going forward, but it does not erase past operational failures. The settlor decision to change the formula is the employer’s to make.
4. Choosing the program
Many errors can be self-corrected, while others call for filing. Where fiduciary breaches are involved, see the Voluntary Fiduciary Correction Program.
An Eight-Step Self-Check Before Year-End
- Pull the current plan document, adoption agreement and every amendment.
- Identify the matching period and any true-up language.
- Request the payroll provider’s match setup and the recordkeeper’s match configuration in writing.
- Compare both to the document line by line.
- Recompute match for a sample of participants with uneven deferrals.
- Extend the review to every affected plan year and to terminated participants.
- Document findings and the chosen correction approach in committee minutes.
- Fix the payroll configuration so the error stops recurring.
Where Sponsors Get Hurt
- Correcting only the current year and ignoring earlier years with the same logic.
- Leaving terminated participants out because they are not on payroll.
- Amending the document to match payroll and treating that as a cure for the past.
- Assuming the recordkeeper or payroll vendor is responsible for the mistake and therefore does not need follow-up.
- Failing to keep written proof of the review, the recalculation and the approval.
- Missing the interplay with testing, since match errors can change results (see nondiscrimination testing).
What You Can Delegate and What You Cannot
Vendors can pull data, run the formula and process corrective deposits. The employer still decides the matching formula, any amendment, and whether to correct through a particular program. Only the employer holds certain facts about pay, bonuses, group classifications and hire dates. A 3(16) plan administrator takes over the recurring administration, including verifying that operations track the document, so a mismatch is caught during routine work rather than by an auditor.
Closing the Gap for Good
A per-pay-period match error is a sign that no one owns the loop between document, payroll and recordkeeper. Admin316 accepts formal appointment as your plan’s ERISA 402(a) named fiduciary, which most providers decline, and we pair it with full 3(16) administration so the person responsible for following the plan terms is accountable for doing it. If you suspect your match logic does not match your document, we can help you find out before an auditor does.
Book a call with Admin316 to review your match calculation and plan operations.
