Do I Need a New EIN for Each Business? Triggers by Entity Type

Whether you need a new EIN for each business comes down to a single test: each legally distinct entity needs its own Employer Identification Number, and an existing business needs a new EIN whenever its ownership or legal structure changes in a way the IRS treats as creating a new taxpayer. Cosmetic changes like a new name or address don’t trigger a new number. A conversion from sole proprietorship to corporation, or a partnership breaking up and re-forming, usually does.¹

Running More Than One Business at the Same Time

If you own two or more legally separate entities, each one gets its own EIN. Two LLCs means two EINs. The IRS treats each entity as its own taxpayer so that income, payroll, and tax liabilities stay on separate books.²

There are two practical exceptions worth knowing before you file extra applications you don’t need.

A sole proprietor who runs several businesses under their own legal identity uses one EIN, or their SSN, for all of them. Those businesses aren’t separate legal entities in the first place, so there’s nothing for a second number to attach to.¹

A single-member LLC with no employees and no excise tax obligations is treated as a “disregarded entity” for federal income tax. The owner can report the LLC’s income under their own SSN or existing EIN instead of getting a new one. That changes the moment the LLC picks up employees or an excise tax liability, at which point it needs its own EIN.³

When a Change to Your Existing Business Requires a New EIN

The specific triggers depend on the entity you have now.

Sole Proprietors

A sole proprietor needs a new EIN when they incorporate, when they take on a co-owner and become a partnership, or when they file a Chapter 7 or Chapter 11 bankruptcy — the bankruptcy estate is a separate taxable entity that needs its own number.⁴ If the owner dies and the estate keeps operating the business, whoever administers the estate applies for a new EIN for it.⁵

Corporations

A corporation needs a new EIN when it receives a new charter from the secretary of state, creates a subsidiary, converts to a partnership or sole proprietorship, or merges with another corporation to form an entirely new one.

A corporation does not need a new EIN when it files for bankruptcy, elects S corporation status, or is the surviving entity in a merger.¹

Partnerships

A partnership needs a new EIN when it incorporates, when one partner takes over the business and continues as a sole proprietor, or when the partnership ends and a new partnership begins in its place. It does not need a new EIN for bankruptcy or for ownership changes that don’t terminate the partnership itself.¹

LLCs

An LLC needs a new EIN when it terminates and re-forms as a new corporation or partnership. A single-member LLC that adds a second owner shifts from a disregarded entity to a partnership for tax purposes, and the IRS treats that conversion as the formation of a new entity — which generally requires a new EIN.³

An LLC keeps its existing EIN when it changes its tax election (say, from partnership to S corporation), when it converts from a partnership to an LLC that’s still classified as a partnership, or when it simply changes its name or location.¹

Changes That Don’t Require a New EIN

Plenty of common updates are administrative and don’t call for a new number. Across every entity type, you keep your existing EIN when you:

Change your business name or register a DBA
Move to a new address or add locations
Change the name or address of an estate’s administrator

You still have to tell the IRS. For a name or address change, send a letter to the IRS service center for your area with your current EIN and both the old and new information. For a change in your responsible party — the person who ultimately owns or controls the business — file Form 8822-B within 60 days.⁶ There’s no direct penalty for missing that deadline, but if the IRS can’t reach your responsible party, you won’t receive notices of tax deficiencies or payment demands, and interest and penalties keep accruing regardless.⁷

How to Apply if You Do Need One

You apply on Form SS-4. It asks for the legal name of the entity, its mailing address, the reason for applying, and the name and SSN or ITIN of the responsible party.⁸

The fastest route is the free online application on irs.gov, which issues the EIN immediately on approval. It’s open Monday through Friday from 6:00 a.m. to 1:00 a.m. Eastern time, Saturdays from 6:00 a.m. to 9:00 p.m., and Sundays from 6:00 p.m. to midnight. Faxed applications take roughly eight business days to process, and mailed ones take about 30 days as of early 2026.⁹

One planning point if you’re setting up several entities at once: the IRS limits each responsible party to one EIN per day across all application methods. Multiple new entities means multiple days.²

An EIN from the IRS is free. Third-party sites often charge up to $300 to file for you, and in April 2025 the Federal Trade Commission sent warning letters to operators that failed to disclose their fee was for something the IRS provides at no cost, with some sites also misrepresenting an affiliation with the agency.¹⁰ Apply directly through irs.gov.¹¹

1
Internal Revenue Service. When to Get a New EIN
2
Internal Revenue Service. Employer Identification Number
3
Internal Revenue Service. Single Member Limited Liability Companies
4
Internal Revenue Service. Publication 908, Bankruptcy Tax Guide
5
Internal Revenue Service. Responsibilities of an Estate Administrator
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Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
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Internal Revenue Service. Form 8822-B, Change of Address or Responsible Party – Business
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Internal Revenue Service. Instructions for Form SS-4
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Internal Revenue Service. Processing Status for Tax Forms
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Federal Trade Commission. FTC Warns Operators of Websites That Charge for an Employer Identification Number and Claim Affiliation With the IRS
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Internal Revenue Service. Get an Employer Identification Number