Form 5500 deadlines and Form 5558 extensions

When is Form 5500 due?

The instructions set one rule for every plan: all forms, schedules and attachments are due “by the last day of the 7th calendar month after the end of the plan” year.^[1] The same date covers Form 5500-SF,^[7] and for a large plan it covers the independent accountant’s report, because that report is an attachment to the return rather than a separate filing. For a plan year that ends on December 31, the return is due July 31 of the next year. For a fiscal year plan, count seven months on from the month the plan year ends and take the last day of that month.

Here is what that produces for the plan year ends most plans use, with the extended date beside it. These dates come from the same engine as the Form 5500 deadline calculator, which takes any date.

What if the due date falls on a weekend or holiday?

It moves forward. “If the filing due date falls on a Saturday, Sunday, or Federal holiday, the return/report may be filed on the next day that is not a Saturday, Sunday, or Federal holiday.”^[1] Form 5558 carries the same rule.^[2] Federal holidays are the eleven days in 5 U.S.C. 6103, and a holiday that falls on a Saturday is observed the Friday before, which is why December 31, 2027 counts as a holiday.^[6] The calendar year 2026 return is the one to watch: July 31, 2027 is a Saturday, so it is due Monday, August 2, 2027.

The roll only decides whether a filing is on time. The extended date is still counted from the original, unadjusted date, so a July 31 that falls on a Saturday still extends to October 15.^[2]

How does Form 5558 extend the deadline?

Form 5558 gives a plan a one-time extension of up to 2 1/2 months.^[1] A properly completed form filed on or before the normal due date is approved automatically “to the date that is no later than the 15th day of the 3rd month after the return/report’s normal due date”.^[2] Three details matter in practice:

• It must be filed by the original due date. A Form 5558 filed after July 31 does not extend a calendar year plan’s return at all.^[2]
• It can be filed electronically. Since January 1, 2025 Form 5558 can go through EFAST2, or on paper to the IRS in Ogden, Utah. Approved copies are not returned, so keep a copy with the plan’s records, as the Form 5500 instructions require.^[1][2]
• It covers Form 8955-SSA only if asked. Form 5558 has a separate line for the Form 8955-SSA extension. An extension of the Form 5500 does not by itself extend Form 8955-SSA, PBGC premium filings or ERISA section 4010 reports.^[1][2]

Is there an extension without Form 5558?

Yes, when the employer has extended its own income tax return. The Form 5500 is automatically extended to the due date of the employer’s federal income tax return if three conditions are all met: the plan year and the employer’s tax year are the same; the employer has an extension of its income tax return to a date later than the normal Form 5500 due date; and a copy of the tax extension is kept with the plan’s records.^[1] A tax-exempt employer that extends its Form 990 with Form 8868 gets the same treatment.^[1]

This route has two limits. It cannot be extended further with a Form 5558, and it cannot run past 9 1/2 months after the plan year ends.^[1] Where the employer’s tax deadline is earlier than the Form 5558 date, Form 5558 gives more time.

When is a short plan year’s return due?

On the last day of the 7th calendar month after the short plan year ends, or by the extended date if an extension applies.^[1] A plan year shortens when the plan starts mid-year, merges, terminates or changes its plan year. For a terminating plan, the short year ends on the date the assets are fully distributed, so the final return is due seven months after the last distribution.^[1] A short plan year can also change when an audit is due: see the audit requirement checker, which applies the deferral in 29 CFR 2520.104-50.

What happens if the deadline is missed?

The return is late from the original due date, even if a Form 5558 was filed. The Department of Labor’s Delinquent Filer Voluntary Compliance Program lets a plan administrator file the late return and pay a reduced penalty of $10 “for each day the annual report is filed after the date on which the annual report was due (without regard to any extensions)”, capped by plan size:^[3][4]

The per plan cap applies when several late years for the same plan go in one submission. A small plan reaches its per return cap at 75 days late, a large plan at 200. The administrator is personally liable, so the penalty cannot be paid from plan assets.^[4]

Outside the program the amounts are of a different order. The 2025 instructions list a Department of Labor penalty of up to $2,739 a day under ERISA section 502(c)(2), and an IRS penalty of $250 a day, up to $150,000, under Code section 6652(e).^[5] The DFVC Program settles the Department of Labor penalty only; the DOL’s program page notes that IRS and PBGC penalties are separate, though those agencies may offer their own relief.^[3] The deadline calculator works out the days late and the program penalty for a given filing date.

How does the audit fit inside the deadline?

For a large plan the accountant’s report is attached to the Form 5500, so the audit has to be finished before the return can be filed. That is a common reason for a large plan to file Form 5558: the extension is time for the audit as much as for the return. Whether a plan is large in the first place depends on its participant count at the start of the year; the audit requirement checker works it out, and large plan vs small plan explains what each category files. For what the auditor will ask for, and who holds each document, see what a 401(k) audit asks for.

Last reviewed November 3, 2026, against the 2025 Form 5500 instructions. Rechecked every January.