Last updated September 2026

What does an IRS letter about a retirement plan usually mean?

A letter from the IRS about a retirement plan is not necessarily an audit. The IRS publishes explanations for a set of notices it sends about a plan’s annual return, the Form 5500 series: reminders that a return may be due, requests for a return its records show as missing, decisions on extension requests, and penalty notices for returns filed late or incomplete. Each notice carries a number, such as CP403 or CP283, in the upper right corner, and the IRS’s notice lookup can be searched by that number.

The number is the most useful thing on the page. It identifies what the IRS is asking for, how long there is to respond and, for plans that missed a filing, which voluntary relief programs may still be available. The Department of Labor (DOL) has its own process for late annual reports, and a written notice from the DOL changes which options remain. This guide sets out the notices plan sponsors most often receive, what each one asks for and where each one falls in that sequence.

The notices plan sponsors most often receive

Sources: IRS, filing notices for Forms 5500, 5500-SF, 5500-EZ or 5558; IRS, Understanding your CP283 notice; IRS, Form 5500-EZ penalty relief FAQs; IRS, Voluntary Correction Program; DOL, Delinquent Filer Voluntary Compliance Program.

How a missing Form 5500 moves through the IRS notice sequence

A Form 5500 series return is generally due on the last day of the seventh month after the plan year ends, July 31 for a calendar-year plan, according to the IRS Form 5500 Corner. An extension can be requested on Form 5558. If the IRS has no record of the return, its notices follow a set timetable:

1. Due dateReturn due. Last day of the seventh month after the plan year ends, or the extended date if Form 5558 was received on time.
2. +15 monthsCP403 mailed. The delay allows time for the DOL to process timely filed returns. The notice sets a 30-day response date.
3. +15 weeksCP406 mailed if there was no response to the CP403 and the DOL still has not received the return.
4. +30 daysResponse window on the CP406. The IRS states that a response within 30 days prevents further action on the account. It does not grant extensions to reply to either notice.

Source: IRS, filing notices for Forms 5500, 5500-SF, 5500-EZ or 5558.

Two practical points follow from the IRS’s own explanations. A CP403 can cross in the mail with a return that was recently filed: the IRS states that a return filed within the last four weeks, using the same employer identification number, plan name and plan number shown on the notice, allows the CP403 to be disregarded. And a CP403 can trace to a mismatch rather than a missing return. If a return was filed under a different EIN, plan name or plan number, the IRS asks for Section I of the notice and a statement explaining the difference.

An example with dates

Applying the IRS timetable to a calendar-year plan whose 2024 return was due July 31, 2025, with no extension requested and no return on the IRS’s record:

Calculated from the intervals the IRS publishes for CP403 and CP406. Actual mailing dates and response dates are those printed on each notice.

The example also shows why a CP403 can arrive long after the underlying deadline: by the time the first IRS notice is mailed, the return has been overdue for more than a year, and IRS late filing penalties are calculated per day.

Reading the notice against the plan’s filing records

Before any reply, the notice has to be matched to the plan’s records. The IRS points to three things it compares: the employer identification number, the plan name and the three-digit plan number. Filed returns can be located through the DOL’s EFAST2 system, described in our guide to finding and downloading Form 5500 filings.

The IRS notice explanations cover several situations that are common in practice:

• The return was filed but under different identifiers. The IRS asks for the notice with Section I completed and a statement explaining why the details differ.
• The plan ended in an earlier year. The IRS treats a plan as having filed its final return only when that return has the final return box checked and shows zero participants and zero assets at year-end. If the earlier return does not show both, the IRS states that it will not show a final return on record, and the return may need to be amended or filing continued until the plan has no assets and no participants.
• The plan is exempt and filed in error in the past. The IRS asks for Section II of the notice and an explanation of the exemption that applies.
• The notice arrived in error. The IRS asks for a copy of the notice and a statement explaining why.

Responsibility for the filing sits with the plan sponsor or plan administrator. The IRS notes that a sponsor may contract with an outside administrator to prepare the form, but that the sponsor or plan administrator remains responsible for its accuracy and signs it, and that the service contract shows whether form preparation is included.

Penalties the notices refer to

Late or incomplete returns can draw penalties from both agencies, and the IRS notes that an incomplete return is not considered filed until it is complete.

Sources: IRS, filing notices; IRS, Understanding your CP283 notice. The DOL penalty is adjusted annually, so it is linked rather than stated here.

Which penalties apply depends on the type of plan. The IRS’s table shows pension plans exposed to both IRS and DOL penalties and all Form 5500-EZ filers exposed to IRS penalties.

Which notice closes which relief program

Both agencies run voluntary programs that reduce penalties for late annual returns, and each program stops being available at a specific point. In many cases, the notice number is critical because eligibility for certain relief programs depends on the type of notice received.

Sources: DOL, DFVCP; DOL, DFVCP fact sheet; IRS, Form 5500-EZ delinquent filing penalty relief FAQs; IRS, CP283.

Three details from the agencies’ own guidance are easy to miss:

• DFVCP relief carries over to IRS penalties. The IRS states that it will not impose its late filing penalties on Form 5500 or 5500-SF filers eligible for DFVCP relief if they also file Form 8955-SSA with the delinquent return, as described in IRS Notice 2014-35.
• One-participant plans use a different program. The DOL lists Form 5500-EZ filers and one-participant plans as ineligible for DFVCP, and the IRS runs its own penalty relief program for late Form 5500-EZ returns, which the IRS states remains available after a CP403 or CP406 but not after a CP283 for that return.
• A denied reasonable cause request ends the IRS program for that return. The IRS states that once a reasonable cause request is denied and the penalty assessed, the same delinquent return is not eligible for its penalty relief program.

The DOL program works on published per-filing and per-plan caps, with a basic daily amount, and the DOL’s program page lists the current figures and its online calculator. Which program fits a particular plan, and whether it is still open, depends on the plan’s type and the notices already received.

Letters that confirm rather than question

Not every IRS letter about a plan signals a problem. Three are routine or favorable:

• CP216F confirms that a Form 5558 extension request was approved and gives the new due date.
• CP214 is a filing reminder for plans that previously filed Form 5500-EZ, and the IRS states that no response is needed.
• A favorable determination letter is issued at a plan sponsor’s request and, according to the IRS, expresses the IRS’s opinion that the plan is qualified in form under section 401(a), giving the employer reliance on that point. The IRS notes that employers are generally not required to apply for one, and that employers adopting a pre-approved plan typically rely on the opinion letter issued to the plan’s provider instead.

A favorable letter speaks to the plan document. How the plan has been operated is a separate question, and operational failures are corrected under EPCRS, described below.

When the letter points to a plan error rather than a filing

Some notices, and some reviews prompted by a notice, surface an operational problem in the plan itself: a missed contribution, an eligibility error, a plan document that was not updated. The IRS corrects these through the Employee Plans Compliance Resolution System (EPCRS), governed by Revenue Procedure 2021-30. The IRS EPCRS overview describes three programs:

Source: IRS, EPCRS overview, page updated July 31, 2026.

Which program is available depends on the failure, the plan’s procedures and whether an audit has begun. The correction methods themselves, and how they apply to a given plan, are covered in our guide to 401(k) plan mistakes and IRS correction options.

After a VCP submission: the compliance statement

When the IRS approves a correction submitted under VCP, it issues a compliance statement. According to the IRS Voluntary Correction Program page, the statement provides that, if the approved correction is completed within 150 days, the IRS will generally not seek to disqualify the plan because of the failures disclosed. The IRS also notes the statement’s limits: it does not protect the plan from other failures the IRS may find during an audit or a determination letter review, and it does not affect participants’ or beneficiaries’ rights under the plan. The IRS advises keeping the statement with the plan’s records.

What a response to an IRS notice typically includes

The IRS’s general guidance on notices, and its explanations for each retirement plan notice, point to a consistent set of elements in a response:

• The notice itself, with the section the IRS specifies completed, since several retirement plan notices ask for Section I, II or III depending on the situation.
• A written statement explaining the plan’s position, whether that is a filed return under different identifiers, a final return, an exemption or disagreement with a penalty.
• Supporting documents, such as the filed return or its EFAST2 filing record.
• The address or fax number on the notice. For CP403 and CP406 notices, the IRS states that only its employee plans entity unit in Ogden can adjust accounts.
• A copy kept with the plan’s records, along with any reply received.

The IRS notice lookup describes the general approach for any notice: review it carefully, keep it, and act by the due date if a response is requested.

Where the Department of Labor fits

The IRS and the DOL share the Form 5500, but they administer different parts of it. The DOL’s civil penalties apply to annual reports required under Title I of ERISA, and its reduced-penalty program is open only until the DOL notifies the plan administrator in writing of a failure to file, which is why an IRS notice and a DOL notice about the same return lead to different options. Our article on IRS and DOL notices discusses how notices from either agency are handled once the underlying issue is identified.

Questions plan sponsors ask about IRS letters

How Leading Retirement Solutions helps

Leading Retirement Solutions’ consulting and correction services include support for the IRS Self-Correction Program, Voluntary Correction Program and Audit Closing Agreement Program, the DOL’s Delinquent Filer Voluntary Compliance Program, reasonable cause letters for delinquent filers and Form 5500 late filing correction. Ongoing plan administration is described on its own page. Employers may wish to consult their tax professional and ERISA counsel regarding their specific circumstances. To talk through a notice, contact our team.

Sources

Every rule in this article comes from the IRS and Department of Labor sources below, each opened and read in September 2026. Figures that change each year are linked rather than printed.

Internal Revenue Service

1. 1IRS filing notices for Forms 5500, 5500-SF, 5500-EZ or 5558CP403, CP406, CP214, CP216F and CP216H: what each means, timing, response windows and sections; no extensions to reply; final return conditions; sponsor responsibility; IRS and DOL penalty exposure; DFVCP relief carrying over to IRS penalties under Notice 2014-35; the Ogden unit that adjusts accounts.Page last reviewed or updated July 23, 2026
2. 2Understanding your CP283 noticeWhat a CP283 means; payment and missing information; penalty amounts before and after 2020; requesting removal with a signed statement.Page last reviewed or updated July 23, 2026
3. 3Understanding your CP216F noticeApproval of a Form 5558 extension request.Checked September 2026
4. 4Form 5500-EZ delinquent filing penalty relief frequently asked questionsThe IRS relief program for one-participant and foreign plans; availability after CP403 or CP406 but not after CP283; Letter 854C on denial of reasonable cause relief.Page last reviewed or updated August 26, 2026
5. 5Understanding your IRS notice or letterLocating the CP or LTR number and the general approach to responding.Page last reviewed or updated May 26, 2026
6. 6Form 5500 CornerThe Form 5500 due date and the Form 5558 extension.Page last reviewed or updated July 20, 2026
7. 7EPCRS overviewSCP, VCP and Audit CAP; Revenue Procedure 2021-30 as the governing guidance.Page last reviewed or updated July 31, 2026
8. 8Voluntary Correction Program (VCP) general descriptionThe compliance statement, the 150-day correction period and the statement’s limits.Page last reviewed or updated March 6, 2026
9. 9Scope and benefit of a favorable determination, opinion or advisory letterWhat a favorable determination letter covers; that employers are generally not required to apply; reliance on opinion letters for pre-approved plans.Checked September 2026

U.S. Department of Labor, EBSA

10. 10Delinquent Filer Voluntary Compliance (DFVC) ProgramProgram eligibility and exclusions, including one-participant plans, Form 5500-EZ filers and recipients of a Notice of Intent to Assess a Penalty; current penalty caps and calculator.Checked September 2026
11. 11Delinquent Filer Voluntary Compliance Program fact sheetEligibility limited to administrators not yet notified in writing by the DOL of a failure to file.Fact sheet dated January 2013

Last reviewed September 2026