The plan sponsor is responsible for ensuring that its plan operates in compliance with the rules related to qualified plans. The plan sponsor is also subject to certain filing requirements. A list of those requirements is included here. Penalties may apply for the late filing or non-filing of required returns and reports. This checklist may be used as a tool to help you meet 401(k) filing requirements. Please see the instructions to the applicable forms or the references for detailed information. This checklist is not intended to be all-inclusive and does not apply to government plans or non-electing church plans. Required to be filed annually: Item Explanation Due to: Form 5500, Annual Return/Report of Employee Benefit Plan or Form 5500-EZ PDF, Annual Return of One-Participant (Owners and Their Spouses) Retirement Plan with applicable schedules and independent auditor's report, if applicable. Form 5500 InstructionsForm 5500-EZ Instructions PDF Required Schedules An administrator or sponsor of an employee benefit plan subject to ERISA must file information about each plan every year. A Form 5500-EZ may generally be filed for a plan that provides benefits solely for an individual (and spouse) who wholly owns a trade or business; or partners or partners (and spouses) in a partnership. IRS/DOL: By the last day of 7th month after the end of the plan year. Form W-2 PDF, Wage and Tax Statement and Form W-3 PDF Transmittal of Wage and Tax Statements Instructions PDF Reports wages and the amount of elective deferrals for a 401(k) plan. Employees: By January 31st following the calendar year. IRS: by February 28th following the calendar year. Required to be filed when applicable: Item Explanation Due to: Form 945 PDF, Annual Return of Withheld Federal Income Tax Instructions PDF Used to report income tax withheld from distributions made from qualified plans. Deposits of the tax with a Form 8109 to an authorized depositary must be made at specified times during the tax year. IRS: By January 31st of the year following the calendar year in which the distribution was made. Form 990-T PDF, Exempt Organization Business Income Tax Return Instructions PDF Used to report gross unrelated business income of $1,000 or more. Generally deposits of the tax with a Form 8109 to an authorized depositary must be made at specified times during the tax year. IRS: By the 15th day of the 4th month after the end of the tax year. Form 1099-R PDF, Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc. Instructions PDF Used to report distributions, including direct rollovers, from qualified plans. Participant: by January 31st following the calendar year of the distribution. IRS: By February 28th of the year following the calendar year of the distribution. Form 5310-A PDF, Notice of Plan Merger or Consolidation, Spinoff or Transfer of Plan Assets or Liabilities; Notice of Qualified Separate Lines of Business (QSLOB) Instructions PDF Used to inform the IRS of plan merger or consolidation, spinoff or transfer of plan assets or liabilities, or QSLOB. IRS: At least 30 days prior to plan merger, consolidation, spinoff or transfer of plan assets to another employer. For QSLOB: By the later of October 15th of the year following the testing year, or the 15th day of the 10th month after the end of the plan year of the plan of the employer that begins earliest in the testing year. Form 5329 PDF, Additional Taxes on Qualified Plans (Including IRAs) and Other Tax-Favored Accounts Instructions PDF Used to report and pay additional taxes. IRS: As an attachment to the Individual Income Tax Return. (Note: filed by participant) Form 5330 PDF, Return of Excise Taxes Related to Employee Benefit Plans Instructions PDF Used to report tax on the following IRC sections: 4971 - minimum funding deficiency 4972 - nondeductible contributions to qualified plans 4973(a)(3) - excess contributions to a 403(b)(7) custodial account 4975 - prohibited transactions 4978, 4978A - certain ESOP dispositions 4979 - excess contributions to plans with cash or deferred arrangements 4979A - certain prohibited allocations of qualified securities by an ESOP 4980 - reversion of qualified plan assets to employers 4980F - failure of applicable plans reducing future benefit accruals to satisfy notice requirements IRS: For taxes due under: 4971 - later of the last day of the 7th month after the end of the employer's tax year or 8 1/2 months after the last day of the plan year that ends with or within the filer's tax year. 4972, 4973(a)(3), 4975, 4978, 4978A, and 4979A - last day of the 7th month after the end of the tax year of the employer or other person who must file this return. 4979 - last day of the 15th month after the close of the plan year to which the excess contributions or excess aggregate contributions relate. 4980 - last day of the month following the month in which the reversion occurred. 4980F - last day of the month following the month in which the failure occurred. Form 5558 PDF, Application for Extension of Time to File Certain Employee Plans Returns Provides a 2 1/2 month extension to file the Form 5500 or 5500-EZ; a 6 month extension to file Form 5330. IRS: By the last day of the 7th month after the end of the plan year for a 5500 extension; before otherwise due for a 5330 extension.