What is Form 5330 and when does an employer file it?
Last updated October 2, 2026
Form 5330 reports and pays excise taxes on prohibited transactions and certain plan failures — most commonly the tax on late deposits of employee 401(k) deferrals. If participant contributions weren't deposited timely, correction typically includes lost earnings plus a Form 5330 filing.
Form 5330 is the excise-tax return of the retirement plan world. The everyday trigger is late deposit of employee deferrals: participant 401(k) contributions must reach the trust as soon as they can reasonably be segregated from company assets (a 7-business-day safe harbor exists for small plans), and late deposits are prohibited transactions carrying a 15% excise tax on the involved amounts.
The standard correction bundle: deposit the contributions, restore lost earnings, file Form 5330 and pay the excise tax, and often report through the DOL's Voluntary Fiduciary Correction Program for a clean release.
Other 5330 triggers include other prohibited transactions, nondeductible contributions, and certain funding shortfalls. The theme: 5330 follows a failure — so payroll timing discipline is the cheapest 5330 strategy available.
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