IRS Form 5558 Extension Guide for Form 5500 & 8955-SSA

Managing employee benefit plans comes with strict reporting deadlines, and missing them can lead to costly IRS and Department of Labor penalties. That’s where IRS Form 5558 comes in. This application allows employers and plan administrators to request extra time to file the Form 5500 series (Form 5500, Form 5500-SF, Form 5500-EZ) and Form 8955-SSA.

Whether you’re a small business owner with a one-participant retirement plan or an administrator handling large employee benefit plans, understanding how to properly use Form 5558 for a 5500 extension is essential for compliance. In this guide, we’ll cover everything you need to know — deadlines, instructions, filing methods (including the new 2025 e-filing option), mailing addresses, FAQs, and best practices.

Highlights of Content

What is Form 5558?

IRS Form 5558, Application for Extension of Time to File Certain Employee Plan Returns, allows employers and plan administrators to request more time to file specific employee benefit plan returns.

The form applies to:

Form 5500 – Annual Return/Report of Employee Benefit Plan
Form 5500-SF – Short Form Annual Return/Report of Small Employee Benefit Plan
Form 5500-EZ – Annual Return of One-Participant (Owners and Their Spouses) Retirement Plan
Form 8955-SSA – Annual Registration Statement Identifying Separated Participants with Deferred Vested Benefits

This extension is crucial because these filings involve complex financial and compliance details. Using Form 5558 helps employers and plan administrators avoid costly IRS penalties while ensuring accuracy.

Who Must File Form 5558?

You must file Form 5558 if:

You are responsible for filing any form in the 5500 series or Form 8955-SSA.
You cannot meet the original filing deadline.
You want to avoid late filing penalties by securing an approved extension.

Employers, plan administrators, and third-party preparers most commonly use Form 5558 when additional time is needed to gather information or reconcile records before filing.

When is the Deadline to File Form 5558?

Form 5558 must be filed on or before the original due date of the return you want to extend.

General Deadlines:

Form 5500, 5500-SF, and 5500-EZ: Due the last day of the 7th month after the plan year ends (e.g., July 31 for calendar-year plans). Form 5558 must be filed by this date to obtain an extension.
Form 8955-SSA: Shares the same deadline as Form 5500 and can also be extended using Form 5558.

Extension Periods:

Filing Form 5558 provides up to a 2½-month extension for the Form 5500 series and Form 8955-SSA.

What Information is Required to Complete Form 5558?

To complete Form 5558, you will need:

Employer/Plan Details
- Employer name, address, and EIN (Employer Identification Number).
- Plan name, three-digit plan number, and plan year beginning and ending dates.
Return Type
- Indicate which return(s) you are requesting an extension for: 5500, 5500-SF, 5500-EZ, or 8955-SSA.
Signature
- The form must be signed and dated by the employer, plan administrator, or an authorized representative. Unsigned forms are not valid.

How to Complete Form 5558 (Line-by-Line Instructions)

Form 5558 is divided into two main parts: Part I – Identification and Part II – Extension Request. Below is a breakdown of how to complete each section correctly.

Part I – Identification

This section collects the filer’s and plan’s identifying information. Accuracy here is essential because errors may cause delays or rejection.

A. Name of filer, plan administrator, or plan sponsor
- Enter the legal name of the employer, plan administrator, or plan sponsor responsible for the filing.
- Include the complete address: number, street, room or suite, city, state, and ZIP code.
- If you use a P.O. Box, follow IRS instructions carefully, as additional requirements may apply.
B. Employer Identification Number (EIN)
- Enter the employer’s 9-digit EIN.
- Do not use a Social Security Number (SSN). If you do not yet have an EIN, you must apply for one using Form SS-4 before filing Form 5558.
C. Name of Plan
- Provide the official plan name exactly as it appears in plan documents and prior filings.
D. Three-digit Plan Number (PN)
- Each plan is assigned a 3-digit plan number.
- If this is your first filing for the plan, start with 001. Use 002, 003, etc. for additional plans.
- Consistency is key: the same plan must use the same number year after year.
E. Plan Year End Date
- Enter the last date of the plan year (month, day, and year).
- For calendar-year plans, this will typically be 12/31/2025.

Part II – Extension of Time to File Form 5500 Series and/or Form 8955-SSA

This section is where you officially request the extension.

Line 1 – First Year Filing Checkbox
- Check this box if you are requesting an extension for the first Form 5500 series filing for a new plan listed in Part I.
- Leave blank if the plan has filed before.
Line 2 – Extension for Form 5500 Series
- Enter the date to which you are requesting an extension to file the Form 5500, 5500-SF, or 5500-EZ.
- The extension period may not exceed the 15th day of the 3rd month after the original due date.
- Example: For a calendar-year plan ending December 31, the original due date is July 31. You may request an extension to October 15.
Line 3 – Extension for Form 8955-SSA
- Enter the date to which you are requesting an extension to file Form 8955-SSA.
- Like the 5500 series, this extension cannot go beyond the 15th day of the 3rd month after the normal due date.
Automatic Approval
- Your extension is automatically approved if:
  1. Form 5558 is filed on or before the normal due date of the return.
  2. The extension date you enter is not later than the maximum period allowed.

Signature Section

The form must be signed and dated by the employer, plan administrator, or an authorized representative.
Unsigned forms will not be processed, and the extension will not be valid.

How to File Form 5558

Beginning January 1, 2025, filers have two options to submit Form 5558:

1. Electronic Filing (EFAST2)

Form 5558 can now be filed online through the EFAST2 system, which is the same platform used to file the Form 5500 series.
Advantages of electronic filing:
- Immediate confirmation of receipt.
- Faster and more reliable processing.
- No risk of mail delays.
To e-file, you must have an EFAST2 User ID and credentials. If you do not have one, you can register at the Department of Labor’s EFAST2 website.

2. Paper Filing with the IRS

You can still file Form 5558 by mailing a paper copy to the IRS.
Always send paper filings using certified mail or an IRS-approved private delivery service to retain proof of timely filing.

Where to Mail Form 5558?

Mail Form 5558 to:

Department of Treasury,

Internal Revenue Service Center,

Ogden, UT 84201-0045

Frequently Asked Questions (FAQs)

1. Can I file Form 5558 electronically?

Yes. Beginning January 1, 2025, Form 5558 can be filed electronically through the EFAST2 system or on paper with the IRS. Electronic filing is faster, provides confirmation of receipt, and reduces mailing delays.

2. How long is the extension period with Form 5558?
You receive up to a 2½-month extension for the 5500 series and Form 8955-SSA.

3. Do I need to file separate Form 5558 applications for multiple plans?
Yes. A separate Form 5558 is required for each plan if you are requesting extensions for more than one.

4. What happens if I miss the deadline to file Form 5558?
If you fail to submit Form 5558 by the original due date, your plan filings will be considered late, and penalties may apply.

5. Do I need IRS approval for Form 5558?
For the 5500 series and 8955-SSA, the extension is automatic once you timely file Form 5558.

Final Thoughts

Form 5558 is an essential compliance tool for employers and plan administrators who need more time to file the Form 5500 series (5500, 5500-SF, 5500-EZ) or Form 8955-SSA. Filing this extension form ensures:

Extra time to prepare accurate returns.
Reduced risk of IRS penalties.
Peace of mind in managing complex benefit plan reporting.

By understanding when, how, and where to file Form 5558, you can keep your retirement plan filings on track while staying compliant with IRS regulations.