What Is an SS-4 Form?
An SS-4 form, also known as an Application for Employer Identification Number (EIN), lets you apply for a unique nine-digit EIN. This IRS form helps a company seek a federal tax ID number, which is the business equivalent of a Social Security number.
Once you provide the business’s details, the IRS reviews the application and approves it if there are no errors. With an EIN, your business can hire employees, open a business bank account, and build business credit.
A responsible party of the business must fill out Form SS-4. The responsible party is an individual who owns or controls the entity. They must be an individual, unless the applicant is a government entity.
Who Needs to Complete Form SS-4?
Businesses don’t always need to get an EIN via Form SS-4. However, an EIN is often necessary if a business wants to complete the following actions:
- Hire employees
- Operate as a partnership or corporation
- File certain tax returns, such as those for employment, excise, alcohol, tobacco, or firearms
- Withhold taxes
- Have a qualified retirement plan, like a Keogh plan
Some other benefits of obtaining an EIN include safeguarding a business owner’s Social Security number and facilitating business financing.
The IRS uses EINs to track entities’ tax duties and financial activities. If your entity must file a tax return, pay taxes, or report income on behalf of others, it typically needs an EIN. Here are some examples of specific entities that need the EIN that Form SS-4 can produce:
- Trusts: To report income, deductions, and distributions on behalf of beneficiaries
- Decedent’s estates: To handle income earned by the estate after someone’s death, such as interest.
- Nonprofit organizations: To apply for tax-exempt status and file annual information returns (Form 990).
- Plan administrators: To report information about employee benefit or retirement plans.
- Government agencies: To report and pay employment taxes or administer certain programs.
- Real estate mortgage investment conduits (REMICs): To file tax returns and report income from mortgage-backed securities.
- Farmers’ cooperatives: To report income and claim deductions related to cooperative operations.
- Household employers: To report and pay employment taxes for domestic workers.
Form SS-4 Changes in 2025
The One Big Beautiful Bill Act (OBBB) did not announce any changes to Form SS-4 for the 2025 tax year. Previous revisions from 2023 remain intact:
- Line 14 update: Eligible filers can elect to file Form 944 annually instead of Forms 941 quarterly. If you expect your annual employment tax liability to be $1,000 or less, you can file Form 944 instead of Form 941. This generally applies if you pay $5,000 or less in wages subject to Social Security, Medicare, and federal income tax withholding ($6,536 or less for US territories).
- Consolidation of Form SS-4PR into Form SS-4 and SS-4(sp): Form SS-4PR was discontinued after 2023. Employers in Puerto Rico should now use Form SS-4 to apply for an EIN. Form SS-4 (sp) is also available if they prefer the Spanish version.
- Guidance for Indian tribal governments: Lines 1 and 9a contain additional information for Indian tribal governments.
How to Fill Out Form SS-4
The SS-4 Form contains 18 lines and additional fields (like the third-party designee and signature areas). Use these Form SS-4 instructions to complete it.
Step 1 – Enter Business Details
Form SS-4 asks for your business information in Lines 1 through 7:
- Line 1: The legal name of the entity for which you’re requesting the EIN. You can provide your individual name if you want the EIN for yourself.
- Line 2: Your business’s trade name (DBA), if applicable.
- Line 3: Name of the administrator, executor, etc. Only applicable if you’re applying for an EIN on behalf of a trust or estate.
- Lines 4a-b: Business’s mailing address.
- Lines 5a-b: Business’s street address (cannot be a PO box).
- Line 6: Address of the business’s physical location.
- Lines 7a-b: Name and SSN/EIN/ITIN of the business’s responsible party.
Step 2 – Define Entity Structure
Next, you’ll define your entity’s structure in the following lines:
- Lines 8a-8c: State whether your entity is an LLC in Line 8a. If yes, use Lines 8b and 8c to state the number of members and clarify whether it was organized in the US.
- Line 9a: Select the entity type from the checklist on Form Ss-4.
- Line 9b: Only fill out if the entity is a corporation. Name the state or foreign country where it was incorporated.
Step 3 – Share Your Reason for the EIN Application
Share your reason for filling out Form SS-4 on Line 10. You can choose from one of the following prewritten options or write in your own:
- Started a new business
- Hired employees
- Compliance with IRS withholding regulations
- Banking purpose
- Changed the type of organization
- Purchased a going business (one that’s financially stable and expected to continue operating for the foreseeable future)
- Created a trust
- Created a pension plan
Step 4 – Provide Additional Business Information
Use the remaining lines (Lines 11 through 18) to provide additional information about your business:
- Line 11: The date the business was acquired or started.
- Line 12: The closing month of the accounting year.
- Line 13: The highest number of employees expected within the next 12 months.
- Line 14: Check the box on line 14 to file Form 944 annually; otherwise, you must file Form 941 quarterly.
- Line 15: The first date wages or annuities were paid.
- Line 16: The category that best describes your business’s principal activity.
- Line 17: The principal line of products or services your business provides.
- Line 18: Whether the applicant entity has ever applied for an EIN before.
Step 5 – Name a Third-Party Designee (if applicable)
If you want someone to receive the entity’s EIN or answer questions about Form SS-4, you can give them permission in the third-party designee section. A third-party designee can be anyone you, as the employer, choose, such as a paid return preparer. Provide their name, phone number, fax number, address, and ZIP code.
Step 6 – Sign Form SS-4
Finish Form SS-4 by providing your signature. When you sign, you ascertain that the details you’ve listed are true to the best of your knowledge. Also, provide the date and your phone and fax number.
How to File Form SS-4
Once you fill out Form SS-4, you can file it via one of two methods for no filing fee:
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By fax: Send a completed Form SS-4 to the appropriate IRS fax number:
- For US domestic applicants: 855-641-6935
- For international applicants: 855-215-1627 (within the US) or 304-707-9471 (outside the US)
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By mail: Once you fill out Form SS-4, you can send it by mail to one of the following addresses:
- For US applicants: Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999.
- For international applicants: Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999.
International applicants have the option to file by phone if they don’t have a legal residence, principal office, or principal place of business in the US or its territories. If you’re an international applicant who meets this condition, call 267-941-1099 to apply for an EIN by phone.
The IRS limits the issuance of EINs to one per responsible party per day. The turnaround time for receiving your EIN depends on the method you use. It typically takes around four business days when you apply by fax, and it can take up to four to five weeks when you apply by mail. You can call 800-829-4933 to check on the status of a Form SS-4 sent by mail.
Online Filing Option
You can apply for an EIN online through the IRS website and receive it immediately upon approval. However, Form SS-4 is needed if you prefer to apply by mail. It’s also needed if you are applying as a foreign applicant or entity without a US taxpayer ID.
Form SS-4 Sample
Below, you can view a sample of Form SS-4 to get an idea of its fields and how to fill it out. When you’re ready to apply for an EIN, you can use Legal Templates’s fillable form to complete it in minutes. Once it’s done, you can download it in PDF or Word format, where it will be ready for you to send to the IRS using your preferred filing method.