IRC 402(g) vs. 415(c): Two Contribution Limits Employers Often Confuse
IRC 402(g) addresses elective deferrals, while IRC 415(c) addresses a broader annual-additions measure. Learn the records, comparisons, and annual controls
IRC 402(g) addresses elective deferrals, while IRC 415(c) addresses a broader annual-additions measure.
IRC 402(g) vs. 415(c): Two Contribution Limits Employers Often Confuse is easiest to manage when the sponsor turns a broad compliance question into a visible sequence of records, classifications, calculations, and review decisions. The practical goal is not to make a spreadsheet look clean. It is to ensure that the data used for the analysis reflects the plan document and the employer’s actual operations. This guide explains participant deferral limits versus total annual additions in a way that helps HR and finance teams prepare a reliable workpaper.
At a glance
- Core question: participant deferral limits versus total annual additions.
- Focus: use a participant-level data trail rather than a summary assumption.
- Reading path: define the scope, compare inputs, then implement a review control.
Define the question before running a report
Annual additions are monitored at the participant level because multiple contribution sources can interact. IRS guidance explains that plans must limit contributions for a participant and identifies annual-additions failures as a common operational issue. [1] The annual numeric limit is indexed and the applicable year should be confirmed from current IRS material rather than copied from an old checklist.
Elective deferrals are employee-directed salary reductions, while employer match, nonelective amounts, after-tax employee contributions, and certain allocations can require separate classification in the annual-additions review. The precise treatment is document- and fact-dependent. A contribution source label in payroll is useful, but it is not a substitute for reading the plan’s allocation provisions.
Compare inputs, not just final percentages
| Input | Question to ask | Why it matters |
|---|---|---|
| Plan document | What population and contribution rules apply? | It sets the intended operational rule. |
| Payroll and HR data | Are classifications and dates complete? | Small data errors can change the analysis. |
| Prior workpapers | What assumptions changed? | They make the process reviewable. |
A simple example illustrates the discipline. If one report counts a worker as eligible while another uses a later entry date, the resulting calculation can be internally consistent but still be based on the wrong input. Resolve that difference at the record level, document the resolution, and rerun the analysis. That practice is more durable than adjusting a final number without an audit trail.
Make the workpaper usable by someone other than its preparer. Identify the plan year, data extraction date, systems used, applicable plan version, and open questions. For every manual adjustment, state the reason, the source evidence, and the reviewer who accepted it. This level of documentation is not bureaucracy for its own sake: it allows the team to distinguish a changed business fact from a changed method, and it makes follow-up work faster when a payroll correction or corporate change is discovered.
Implement a repeatable annual control
Build a participant-level ledger with separate columns for each contribution source, compensation input, pay period, posting date, and allocation status. Run a preliminary review before any year-end employer allocation, then run a final review after true-ups and forfeiture allocations are known. The control should identify the person, source, calculation date, reviewer, and any unresolved exception.
- Freeze a versioned census or contribution ledger for the review date.
- Check material exceptions against source records and plan language.
- Record the selected method, assumptions, and reviewer conclusion.
- Escalate a failed, borderline, or unexplained result before corrective transactions occur.
Decision flow
- Identify rule: identify the governing limit, date, and affected group.
- Model impact: model cost, eligibility, and interaction with other rules.
- Apply control: apply the rule through payroll or plan controls.
- Recheck: recheck inputs, corrections, and retained support.
Use the flow: collect the source records, compare the applicable classifications, implement a documented action, and review the result before filing or communicating it.
Review exceptions with the right evidence
When an exception appears, preserve the ledger and the plan provisions that govern the contribution. Confirm whether the issue is a data classification problem, an allocation problem, or an actual excess. IRS correction guidance is a starting point, but the correction sequence, attributable earnings, reporting, and deadlines can require specialist analysis. [1] Avoid treating a refund or reclassification as automatic without that review.
| Review area | Evidence | Control response |
|---|---|---|
| Deferrals | Employee salary-reduction source | Monitor separately from employer allocations |
| Employer funding | Match, nonelective, or true-up amount | Recheck after year-end calculation |
| Forfeiture allocation | Plan-directed allocation source | Include in final participant review |
Practical questions for the plan team
Ask whether the workpaper can be reproduced from the same inputs next month, whether an independent reviewer can understand each classification, and whether late information is captured in a controlled update. The answer should include documents and data—not only an email statement that the test was completed. This approach also separates operational diagnosis from legal interpretation, which reduces the risk of an unsupported conclusion.
Set a calendar that matches the operational sequence. Payroll and HR should know the cutoff for their extracts; the recordkeeper or administrator should know when preliminary and final information is due; and the reviewer should receive a concise exception log rather than an unexplained total. When a merger, acquisition, payroll conversion, plan amendment, or major workforce change occurs, add a targeted midyear check. A predictable cadence gives the team time to investigate facts before a deadline turns a routine review into an emergency. It also creates clear ownership: data owners certify inputs, plan personnel confirm design assumptions, and advisers address interpretations that depend on law or formal correction guidance.
Finally, record the decision made after review: no change, corrected data, amended process, or further professional analysis. That closing entry prevents the same exception from returning without context in the next plan year.
Takeaway
Use separate controls because passing one limit does not establish compliance with the other. Treat the test or limit as an annual control with named data owners, a retained workpaper, and professional escalation for facts that affect qualification or correction.
Editorial disclaimer: This article is general educational information, not tax, legal, actuarial, investment, or ERISA advice. Plan documents, facts, and current official guidance should be reviewed with qualified advisers before a compliance decision or correction is made.
References
- [1] Internal Revenue Service, Fixing common plan mistakes—Failure to limit contributions for a participant. https://www.irs.gov/retirement-plans/fixing-common-plan-mistakes-failure-to-limit-contributions-for-a-participant
- Supporting source: Internal Revenue Service, Retirement topics—Contributions. https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-contributions