Under 401(k) deposit rules for employers, money withheld from a worker’s paycheck for elective deferrals or loan repayments becomes a plan asset the moment it’s withheld, and the employer has to move it into the plan trust as soon as it can reasonably be separated from company funds.1eCFR. 29 CFR 2510.3-102 – Definition of Plan Assets — Participant Contributions Employer matching and profit-sharing contributions run on a different, more forgiving clock tied to the tax return due date. Missing either deadline creates a fiduciary breach, a prohibited transaction, or both, and the cost lands on the employer.
Deadline for Employee Deferrals and Loan Repayments
The Department of Labor’s standard is “as soon as administratively feasible.” That means the deposit should happen on the earliest date the employer’s payroll process actually allows, which is often within a few business days of the paycheck.2U.S. Department of Labor. FAQs About Retirement Plans and ERISA
There is an outer ceiling on top of that standard: deposits cannot be later than the 15th business day of the month after the payroll date. Amounts withheld in January must reach the plan trust by the 15th business day of February at the absolute latest.1eCFR. 29 CFR 2510.3-102 – Definition of Plan Assets — Participant Contributions Treat that date as a ceiling, not a target. An employer that normally deposits in two days but suddenly waits ten is late, even though the 15-day cap hasn’t passed. The DOL measures timeliness against what your systems actually can accomplish.
The Seven-Business-Day Safe Harbor for Small Plans
A plan with fewer than 100 participants at the start of the plan year qualifies for a bright-line safe harbor. If you deposit employee deferrals and loan repayments within seven business days of the withholding date, the deposit is automatically treated as timely.1eCFR. 29 CFR 2510.3-102 – Definition of Plan Assets — Participant Contributions The safe harbor is optional. A small employer can still deposit faster and rely on the general “as soon as feasible” rule, but hitting the seven-day mark eliminates any argument about whether the deposit could have been made sooner.
Larger Plans Have No Safe Harbor
Plans with 100 or more participants don’t get the seven-day benchmark. Compliance is judged against the employer’s own operational reality. The DOL looks at payroll systems, internal processes, and deposit history to decide what’s feasible for that specific company. An employer that has consistently deposited funds within two or three days of payroll can’t start taking a week without an explanation.3SHRM. DOL Rule Gives Small Plans 7-Day Safe Harbor to Deposit Employee Contributions Document your deposit timelines and treat your fastest achievable turnaround as the benchmark.
Deadline for Employer Matching and Profit-Sharing Contributions
Employer contributions follow a different clock. Because these funds were never part of an employee’s paycheck, the “as soon as feasible” rule doesn’t apply. The IRS sets the deadline through the tax-deduction rules: employer contributions are deductible for a given tax year if they are deposited by the due date of the employer’s federal income tax return, including extensions.4Internal Revenue Service. Issue Snapshot – Deductibility of Employer Contributions to a 401(k) Plan Made After the End of the Tax Year
For a calendar-year C corporation, that’s April 15, extending to October 15. For an S corporation or partnership, March 15, extending to September 15. Sole proprietors follow the Form 1040 schedule of April 15, extending to October 15. The employer must deposit the contribution and treat it as allocated to the prior tax year to claim the deduction on that year’s return.5Office of the Law Revision Counsel. 26 USC 404 – Deduction for Contributions of an Employer to an Employees Trust or Annuity Plan and Compensation Under a Deferred-Payment Plan
Watch the plan document. If the plan says matching contributions must be deposited each pay period, that stricter schedule controls, regardless of the more generous IRS deadline.4Internal Revenue Service. Issue Snapshot – Deductibility of Employer Contributions to a 401(k) Plan Made After the End of the Tax Year Ignoring the plan’s own terms creates an operational failure that can jeopardize the plan’s tax-qualified status.
Penalties for Late Deposits
A late deposit of employee deferrals is two violations at once: a fiduciary breach under ERISA and a prohibited transaction under the Internal Revenue Code. Three cost layers can hit the employer.
Lost Earnings
The employer has to make the plan whole by contributing the investment returns participants would have earned if the money had been deposited on time. The DOL provides an online calculator that computes lost earnings using the IRS underpayment interest rate under IRC Section 6621(a)(2), compounded daily.6U.S. Department of Labor. Voluntary Fiduciary Correction Program (VFCP) Online Calculator For a deposit only a day or two late, the number may be trivial. For deposits weeks or months late, the amounts grow, and they come from the employer, not from plan assets.
Prohibited Transaction Excise Tax
The IRS imposes an initial excise tax of 15% on the “amount involved” for each year or part of a year the prohibited transaction stays uncorrected. For late deposits, the IRS treats the amount involved as the interest on the late deferrals rather than the full contribution.7Internal Revenue Service. Instructions for Form 5330 (Rev. December 2025) If the problem still isn’t corrected by the end of the taxable period, a second-tier tax of 100% of the amount involved applies.8Office of the Law Revision Counsel. 26 USC 4975 – Tax on Prohibited Transactions The employer reports and pays this tax on Form 5330, due by the last day of the seventh month after the end of the employer’s tax year.
DOL Civil Penalty
If the DOL investigates and secures a recovery, whether by settlement or court order, it can assess an additional civil penalty of 20% of the amount recovered. That penalty is reduced by any excise tax the employer already paid to the IRS for the same transaction, so the two don’t stack at full value, but the combined exposure adds up.9eCFR. 29 CFR Part 2570 Subpart D – Procedure for the Assessment of Civil Penalties Under ERISA Section 502(l)
How to Correct a Late Deposit
Two federal programs let employers fix late deposit problems voluntarily. Using them before the government finds the issue reduces the financial and legal fallout considerably.
DOL Voluntary Fiduciary Correction Program
The VFCP is the primary correction path for late employee deferrals. The employer calculates lost earnings with the DOL’s online calculator, deposits the missing earnings into the plan, and submits a correction application.6U.S. Department of Labor. Voluntary Fiduciary Correction Program (VFCP) Online Calculator Once the DOL accepts the correction and issues a no-action letter, the employer also qualifies for a prohibited transaction exemption under PTE 2002-51, which can eliminate the IRC Section 4975 excise tax entirely. The exemption only applies when the late contributions were deposited within 180 calendar days of the withholding date.10Federal Register. Prohibited Transaction Exemption (PTE) 2002-51 Contributions that sat in the employer’s account longer than 180 days won’t qualify for the excise tax exemption, even if the VFCP correction itself is accepted.
IRS Self-Correction Under EPCRS
The IRS Employee Plans Compliance Resolution System allows employers to self-correct certain operational failures without filing anything with the IRS or paying a fee. To use self-correction, the employer must have had reasonable practices and procedures in place to promote compliance. The late deposit has to be a genuine mistake, not a systemic failure.11Internal Revenue Service. Steps to Self-Correct Retirement Plan Errors The employer corrects the problem, restores any lost amounts, and keeps thorough documentation for a future audit. For significant failures, correction must be completed by the end of the third plan year after the year the failure occurred.12Internal Revenue Service. Employee Plans Compliance Resolution System (EPCRS) – Revenue Procedure 2021-30
The two programs address different sides of the same problem. VFCP handles the DOL fiduciary side and can produce the excise tax exemption. EPCRS handles the IRS qualification side and protects the plan’s tax-favored status. Employers with late deposits often need to work through both.
Reporting Late Deposits on Form 5500
Late deposits also show up on the plan’s annual Form 5500. Plan administrators must report delinquent participant contributions on Line 4a of Schedule H (large plans) or Schedule I (small plans). Every late deposit for the plan year must be listed, even if the employer already corrected it through the VFCP. Plans subject to an annual audit must include an attachment labeled “Line 4a — Schedule of Delinquent Participant Contributions” with the details.13U.S. Department of Labor. FAQs About Reporting Delinquent Participant Contributions on the Form 5500
Checking “yes” on Line 4a is one of the fastest ways to draw DOL attention, so employers who spot a late deposit have a strong incentive to clean it up through the VFCP before the Form 5500 filing. Filing alone doesn’t resolve the issue, but disclosing it shows the plan administrator is aware and has acted, which matters when the DOL later weighs whether penalties are warranted.