April 8, 2024

Everything You Need to Know About Form SS-4

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Form SS-4 is one of the most important forms you'll need to submit as a new business owner. Filing form SS-4 with the IRS enables you to get an EIN (Employer Identification Number) for your business.

EINs are nine-digit numbers that the IRS uses to track company activity. You'll need one for various tasks such as paying taxes, hiring employees, and even opening a bank account. Even if you don't yet need an EIN, it's a good idea to get one as soon as possible in order to prepare for future changes. In this guide, we’ll explain how to file Form SS-4 and acquire an EIN for your new company.

Do I Need to File Form SS-4? 

An EIN is required in order to conduct many basic business functions, beyond just the ability to hire employees. Without an EIN, you won’t be able to pay federal taxes, open a business checking account, or apply for business loans. 

Corporations and partnerships are required to file Form SS-4, as are businesses who have employees or pay employment taxes. The same applies to trusts, estates, and non-profit organizations.

If you operate an LLC and want it to be taxed as an S-Corporation, you’ll need an EIN in order to file Form 2553.

You’re not required to file Form SS-4 in every circumstance. If you’re a sole proprietor or have an LLC with no employees, for example, you don’t technically need an EIN. In this case, you can use your personal social security number as your taxpayer identification instead.

As mentioned above, just because you don't need an EIN today doesn't mean that you shouldn't. Most successful businesses will eventually run into a situation where an EIN is required.

How to File

Filing Form SS-4 is as simple as filling out your information and submitting it to the IRS. However, it's worth noting that you can file online or through mail or fax. Online filings are only available to companies who have an owner/stakeholder with an SSN or ITIN (individual taxpayer identification number). If you don't have one of these, you should consider getting an ITIN first so that you can expedite your Form SS-4 filing online.

This form has just one section, so let's look at it line by line.

  1. Begin with writing the legal name of your business. If you’re a sole proprietor, write your name instead. 
  2. If the trade name of your business is different from what you wrote on Line 1, indicate it here. 
  3. Enter the name of the trustee, or the name of the fiduciary in charge of the estate. Corporations should skip this line.  
  4. Enter the business’ mailing address.  
  5. If the business’ physical address is different from the mailing address listed in Line 4, indicate so here. 
  6. Indicate the county and state in which the business is primarily located. 
  7. Line 7a asks you to list the ”responsible party.” This is the person filling out the form, and could be the business’ owner, an officer or a partner. It should be an individual, assuming the applicant is a government entity. In 7b, enter the party’s social security number, EIN or Individual Taxpayer Identification Number (ITIN). 
  8. Indicate whether the business is an LLC. If so, list the number of members, and whether it was organized in the United States. 
  9. In Line 9a, indicate the type of entity for which you’re filing Form SS-4 — even if you’re an LLC and checked “Yes” in Line 8. You may have to provide additional information, depending on the selection. Enter your social security number if you’re a sole proprietor, the tax form you plan to file if your business is a corporation, and so on. 
  10. Indicate your reason for applying for an EIN. This is straightforward; if you’re starting a new business, select “Started a new business.” If your reason is not listed, select “Other” and specify the reason. You must make a selection on this line. 
  11. List the date your business started (or the date you acquired it). This information should be readily available within state documents. 
  12. Enter the closing month of the business’ accounting year. Many businesses use the calendar year for accounting purposes, in which the closing month would be December. 
  13. Enter the highest number of employees expected in the next 12 months. Businesses with no expected employees should skip this line. 
  14. Indicate whether you wish to file Form 944. Businesses with expected employment tax liability of $1,000 per calendar year may elect to file Form 944 one per year, rather than file Form 941 every quarter. 
  15. Enter the first date wages or annuities were paid. 
  16. Select the description that best describes the principal activity of your business. If your business is a restaurant, for example, select “Accommodation & food service.” You must make a selection on this line; if none of the options fit, select “Other” and specify your business’ principal activity. 
  17. Describe your business in more detail here by indicating its primary services and/or products. 
  18. Indicate whether your business has ever applied for or received an EIN before. If so, enter the business’ previous EIN. 

Finally, sign and date the form and submit it to the IRS using your preferred methods.


At just one page long, Form SS-4 is relatively quick and easy to fill out. The required information shouldn’t take long to acquire, particularly if the applicant is a new or small business. As we’ve already noted, filing Form SS-4 has advantages even for business entities that are not required to do so.

Instead of mailing or faxing Form SS-4 to the IRS, owners with an SSN or ITIN may apply online through the IRS website. The online portal is available weekdays from 7 a.m. to 10 p.m. Eastern Standard Time. The session will expire after 15 minutes, so be sure to have all of the necessary information before you begin.

If you incorporate your business through Firstbase, we’ll take care of all the necessary paperwork to get an EIN for your company. Simply fill out the initial incorporation form and let us handle the rest. We also offer exclusive discount on ITIN applications through our partner The ITIN — get $50 off with code FIRSTBASE50.

Haven't incorporated your business yet? Click here to start the incorporation process now.

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