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What is Form SS-4?
Form SS-4 is the Internal Revenue Service (IRS) application used to obtain an Employer Identification Number (EIN), also known as a Federal Tax Identification Number. An EIN is a unique nine-digit number assigned to businesses and organizations operating in the United States, functioning similarly to a Social Security number for businesses.
Who Needs to File Form SS-4?
You must file Form SS-4 if you:
• Start a new business
• Hire employees
• Form a corporation, partnership, or LLC
• Purchase or inherit an existing business
• Open a business bank account
• Create a pension plan
• Form a trust (except certain grantor-owned revocable trusts)
• File for bankruptcy under Chapter 7 or 11
Sole proprietors without employees who don't meet any other requirements can typically use their Social Security number instead of an EIN.
Key Deadlines and Requirements
The IRS doesn't set a specific deadline for obtaining an EIN, but you need one:
• Before hiring employees (must have EIN before first payroll tax return is due)
• Before filing business tax returns
• When opening business bank accounts
• When applying for business licenses
For new businesses with employees, apply for an EIN at least two weeks before you need to file payroll taxes or other business documents.
Information Required on Form SS-4
The form requires:
• Legal name of business entity
• Trade name (if different)
• Business address and mailing address
• Type of entity (corporation, partnership, LLC, etc.)
• Reason for applying
• Date business started or acquired
• Principal business activity
• Number of employees expected in next 12 months
• First date wages were or will be paid
• Principal officer, partner, or responsible party information
• Tax classification
Special Requirements for International Applicants
International applicants must provide:
• Country of incorporation
• Foreign address
• Additional documentation proving business legitimacy
Filing Steps and Procedures
Online Application
1. Visit the IRS website and access the online EIN application
2. Complete all required fields
3. Submit application during business hours (7am-10pm Eastern time, Monday-Friday)
4. Receive EIN immediately upon approval
Paper Application
1. Download Form SS-4 from IRS.gov
2. Complete all sections clearly and accurately
3. Mail to appropriate IRS address (varies by state)
4. Wait 4-5 weeks for processing
By Fax
1. Complete Form SS-4
2. Fax to appropriate IRS fax number
3. Receive response within 4 business days
4. Include return fax number
Common Mistakes to Avoid
• Applying for multiple EINs unnecessarily
• Providing incomplete responsible party information
• Using incorrect business classification
• Listing wrong starting date for business
• Failing to sign the form (paper applications)
• Applying with multiple methods simultaneously
• Using unofficial websites that charge fees for EIN application
Consequences of Incorrect Filing or Non-Filing
Business Operations Impact
• Unable to open business bank accounts
• Cannot obtain necessary business licenses
• Problems with vendor relationships
• Difficulty securing contracts
Tax Implications
• Penalties for late payroll tax deposits
• Unable to file business tax returns
• Potential IRS notices and inquiries
• Risk of tax compliance issues
Corrective Actions
If you discover errors on your SS-4:
1. Write to the IRS explaining the error
2. Provide documentation supporting the correction
3. Include your EIN and business information
4. Wait for IRS response (typically 4-6 weeks)
Remember that EINs are permanent and generally can't be cancelled. Even if you close your business, the EIN remains assigned to your business entity. If you need to update information after receiving your EIN, use Form 8822-B to notify the IRS of changes to your business address or responsible party.
The IRS issues only one EIN per day per responsible party, so plan accordingly if you need multiple EINs for different entities. For fastest processing, apply online during regular business hours when live customer service is available to assist with any issues that arise during the application process.
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Frequently Asked Questions
What is an EIN and why does a business need one?
An Employer Identification Number (EIN) is a unique nine-digit number assigned by the IRS to businesses and organizations operating in the United States, functioning similarly to a Social Security number for individuals. You need an EIN before hiring employees, filing business tax returns, opening business bank accounts, and applying for business licenses. Sole proprietors without employees who don't meet any other requirements can typically use their Social Security number instead.
How long does it take to receive an EIN after applying?
Processing time depends entirely on how you apply — online applications submitted during business hours (7am–10pm Eastern time, Monday–Friday) result in an EIN being issued immediately upon approval. Fax applications are processed within 4 business days, provided you include a return fax number. Paper applications mailed to the IRS take the longest, with a wait time of 4–5 weeks for processing.
When should a new business apply for an EIN before hiring employees?
New businesses with employees should apply for an EIN at least two weeks before they need to file payroll taxes or other business documents. The IRS requires you to have your EIN in place before your first payroll tax return is due, so waiting until the last minute can create compliance problems. Late payroll tax deposits can result in penalties, making it critical to secure your EIN well in advance of your first payroll.
What happens if errors are discovered on a previously filed Form SS-4?
If you discover errors on your SS-4, you should write to the IRS explaining the error, provide supporting documentation, and include your EIN and business information. The IRS typically takes 4–6 weeks to respond to correction requests. It's important to note that EINs are permanent and generally cannot be cancelled — even if you close your business, the EIN remains permanently assigned to that business entity.
Can a business owner apply for multiple EINs at once or through multiple methods?
The IRS issues only one EIN per day per responsible party, so you must plan accordingly if you need multiple EINs for different entities. Applying with multiple methods simultaneously is a common mistake to avoid, as it can create confusion and processing delays. Additionally, taxpayers should be cautious of unofficial websites that charge fees for EIN applications, since applying directly through the IRS is free.
About the Author
Tax Writer
Markos Banos is a tax professional at IRS.com with expertise in U.S. federal and state tax law. Their articles are written to help taxpayers understand complex tax topics in plain English.