Form SS-4 & employer identification number (EIN)

• A sole proprietor without employees who isn’t required to file any excise tax return and hasn’t established a pension, profit-sharing, or retirement plan doesn't need an EIN (but can get one). In this instance, the sole proprietor uses his or her Social Security number (instead of an EIN) as the taxpayer identification number. However, if at any time the sole proprietor hires an employee, needs to file an employment or excise tax return, or is establishing a pension, profit-sharing, or retirement plan, then the sole proprietor will need an EIN for the business and can't use his or her social security number.
• If you have an existing EIN as a sole proprietor and become a sole owner of a Limited Liability Company (LLC) that has employees, needs to file an employment or excise tax return, or is establishing a pension, profit sharing, or retirement plan, you need to get a separate EIN for the LLC.

• Publication 1635, Employer Identification Number - Understanding Your EIN
• Publication 334, Tax Guide for Small Business (For Individuals Who Use Schedule C)
• Form SS-4, Application for Employer Identification Number (PDF)
• Small business and self-employed tax center

• An EIN is a type of TIN used to identify taxpayers that are required to file various business tax returns. EINs are used by employers, some sole proprietors, corporations, partnerships, certain individuals, trusts and estates, and other business entities.
• If you're required to report employment taxes or excise taxes or to give tax statements to employees or annuitants, you need an EIN.

• Publication 334, Tax Guide for Small Business (For Individuals Who Use Schedule C)
• Publication 3402, Taxation of Limited Liability Companies
• Publication 1635, Employer Identification Number - Understanding Your EIN
• Small business and self-employed tax center
• Taxpayer identification numbers (TIN)

If you already have an EIN, and the organization (structure) or ownership of your business changes, you may need to apply for a new number.

Some of the circumstances under which a new number may be required are as follows:

• An existing business is purchased or inherited by an individual who'll operate it as a sole proprietorship.
• A sole proprietorship changes to a corporation or a partnership.
• A sole proprietorship files for bankruptcy under Chapter 7 (liquidation) or Chapter 11 (reorganization).
• A sole proprietorship establishes a pension, profit-sharing, or retirement plan.
• A partnership changes to a corporation.
• A corporation changes to a partnership.
• An individual owner of a sole proprietorship dies, and the estate takes over the business.

This list isn't all inclusive. Please refer to Employer ID numbers.

• Publication 1635, Employer Identification Number - Understanding Your EIN
• Do you need a new EIN?
• Form SS-4, Application for Employer Identification Number (PDF)
• Small business and self-employed tax center

In general, businesses are required to obtain the TIN from vendors they pay if they're required to file any information return, document or other statement that calls for the TIN. It’s a good business practice to obtain TIN information from a vendor even if you’re unsure whether any information return, document or other statement will be required. Form W-9, Request for Taxpayer Identification Number and Certification can be used to make the request. The business should also maintain the verification of these numbers in its records.

If the vendor is a foreign person, the IRS suggests that you request that the vendor complete the appropriate Form W-8. For more information on completing these forms and when a U.S. TIN is required to be included, see the Instructions for the Requester of Forms W–8BEN, W–8BEN–E, W–8ECI, W–8EXP, and W–8IMY.

• General Instructions for Certain Information Returns (Forms 1096, 1097, 1098, 1099, 3921, 3922, 5498, and W-2G)
• Publication 515, Withholding of Tax on Nonresident Aliens and Foreign Entities