You can hold as many Employer Identification Numbers as you have separate business entities. The IRS issues one EIN per entity for the life of that entity, so if you own four LLCs and a corporation, you will have five EINs. There is no ceiling on the total, but the IRS caps applications at one per responsible party per business day, which sets the pace at which you can add new ones.1Internal Revenue Service. 21.7.13 Assigning Employer Identification Numbers (EINs)
One EIN Per Entity
Each corporation, LLC, partnership, or trust gets exactly one EIN, and that number stays with the entity for its entire existence.2Internal Revenue Service. Employer Identification Number Federal regulations require each taxpayer to furnish a single identifying number, and the IRS uses it to track the entity’s complete filing history.3eCFR. 26 CFR 301.6109-1 – Identifying Numbers Two EINs for the same business would split its records, so the IRS does not permit it.
A “Doing Business As” name is not a separate entity. If one LLC operates three brands, all three brands share the LLC’s single EIN. You also do not need a new number when the business changes its name, address, or responsible party.2Internal Revenue Service. Employer Identification Number
Multiple Entities Mean Multiple EINs
Nothing in the tax code limits how many businesses one person can form. Three LLCs and two corporations produce five EINs, one for each. The IRS treats every business as a distinct legal person, so common ownership is irrelevant to the count.
Something worth keeping straight: you do not personally own the EIN. It belongs to the entity. Sell the LLC, and the EIN travels with it to the new owner along with the tax history attached to that number.
The One-Per-Day Application Limit
Since May 21, 2012, the IRS has limited each responsible party to one EIN application per business day.1Internal Revenue Service. 21.7.13 Assigning Employer Identification Numbers (EINs) The cap applies across every method: online, fax, phone, and mail. A second application submitted the same day will be rejected.
The responsible party is the individual who ultimately owns or controls the entity and has practical authority over its assets. For a corporation, that is usually the principal officer; for a partnership, a general partner; for a trust, a grantor, owner, or trustee.4Internal Revenue Service. Instructions for Form SS-4 (12/2025) The limit is tied to that person’s SSN or ITIN, so forming five new businesses at once still means spreading the applications across five separate business days.
When a Change Requires a New EIN
Sometimes a business that already has an EIN needs a new one because its structure has changed. The general rule is that a change in ownership or entity type triggers a new number.5Internal Revenue Service. When to Get a New EIN The specific triggers vary by entity type:
- Sole proprietors need a new EIN if they incorporate, form a partnership, or file for bankruptcy.
- Corporations need a new EIN if they receive a new charter from the secretary of state, create a subsidiary, convert to a partnership or sole proprietorship, or merge to form a new corporation. The surviving corporation in a merger keeps its existing EIN.
- Partnerships need a new EIN if they incorporate or if the existing partnership terminates and a new one begins. A change in partners that does not end the partnership does not require a new number.
- LLCs need a new EIN if they terminate and reform as a corporation or partnership, or if a single-member LLC has to start filing employment or excise taxes.
- Trusts generally need a separate EIN for each trust, and a new one when a revocable trust becomes irrevocable or a living trust converts to a testamentary trust.5Internal Revenue Service. When to Get a New EIN
When You May Not Need an EIN at All
Not every business owner needs even one EIN. A sole proprietor with no employees and no excise tax obligations can file using a Social Security number. Many still choose an EIN to keep their SSN off business paperwork or because a bank requires it to open a business account, but the number is optional in that situation, and the owner is limited to one for that sole proprietorship.
A single-member LLC that the IRS treats as a disregarded entity works similarly. With no employees and no excise tax liability, the owner can use an SSN or personal EIN for income tax reporting. Once the LLC hires employees or owes excise taxes, it must obtain its own EIN for employment tax purposes.6Internal Revenue Service. Single Member Limited Liability Companies In practice, most new single-member LLCs end up with an EIN anyway because banks and state agencies commonly require one.
How to Apply
Applying for an EIN is free directly from the IRS.7Internal Revenue Service. Get an Employer Identification Number Three methods are available:
- The online EIN Assistant, which issues the number immediately upon approval and lets you download the CP 575 confirmation letter right away.
- Fax submission of Form SS-4, which typically produces a response within four business days.
- Mail submission of Form SS-4, which takes roughly four to five weeks.8Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025)
Every application asks for the entity’s legal name as it appears on formation documents, any trade name, the responsible party’s name and SSN or ITIN, the entity type, and the reason for applying.9Internal Revenue Service. Form SS-4 (Rev. December 2025) – Application for Employer Identification Number The responsible party has to be a person, not another entity, unless the applicant is a government body.8Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025)
Skip the Paid Third-Party Sites
Because the IRS charges nothing, any site asking for payment is not the IRS. Third-party operators have charged up to $300 for an EIN application, often using IRS-like logos, colors, and domain names to suggest a government affiliation they do not have.10Federal Trade Commission. FTC Warns Operators of Websites That Charge for an Employer Identification Number and Claim Affiliation With the IRS If a fee appears, close the tab and go directly to irs.gov.
One last point worth remembering as you accumulate businesses and numbers: an EIN is permanent. It does not expire, it cannot be transferred to a different entity, and the IRS never reassigns it after a business closes. Each number you receive stays tied to the entity it was issued to for as long as the IRS keeps records.