Do I Need a Separate EIN for Each Business I Own?

Whether you need a separate EIN for each business you own depends on how each one is legally organized, not on how many you run. If you operate several ventures as a sole proprietor, or as a single-member LLC that the IRS treats as disregarded, one EIN (or even just your Social Security Number) covers all of them. If you formed separate corporations, partnerships, or multi-member LLCs, each entity is its own taxpayer and needs its own EIN.1Internal Revenue Service. When to Get a New EIN

When One EIN Covers Everything You Do

A sole proprietor is a single taxpayer in the eyes of the IRS, no matter how many businesses they run. You can operate a landscaping company and a freelance consulting practice under different “Doing Business As” names and still file one Schedule C-driven Form 1040 for all of it. The IRS states plainly that sole proprietors who own multiple businesses do not need a new EIN for each one.1Internal Revenue Service. When to Get a New EIN Income and expenses from every venture flow through the same personal return.2Internal Revenue Service. Sole Proprietorships

The same logic applies to a single-member LLC that the IRS treats as a disregarded entity for federal income tax. Because the LLC isn’t seen as separate from its owner, extra EINs aren’t required for different branches or activities inside it. A disregarded single-member LLC with no employees and no excise tax liability can use the owner’s SSN and doesn’t need an EIN at all.3Internal Revenue Service. Single Member Limited Liability Companies

One exception catches people off guard. A disregarded single-member LLC must obtain its own EIN, and use it, for employment tax reporting once it has employees. For wages paid after January 1, 2009, the LLC is treated as a separate entity for employment tax and certain excise taxes, even though it stays disregarded for income tax.3Internal Revenue Service. Single Member Limited Liability Companies If your single-member LLC runs payroll, it needs its own EIN even though your income still lands on your personal return.

When Each Business Needs Its Own EIN

Once you form a separate legal entity, it becomes its own taxpayer. If you set up two LLCs instead of running two ventures inside one, each LLC files independently and needs its own identification number. Every corporation, every multi-member LLC, and every partnership you create requires an EIN of its own. A multi-member LLC needs an EIN regardless of how it’s taxed.4Internal Revenue Service. LLC Filing as a Corporation or Partnership

Parent-subsidiary structures work the same way. When a corporation creates a subsidiary, that subsidiary must obtain its own EIN. The IRS treats each subsidiary as a separate corporate taxpayer with independent filing obligations, even when the parent owns 100% of it.1Internal Revenue Service. When to Get a New EIN

Keeping separate EINs for separate entities is more than a technicality. Mixing identification numbers across different legal entities creates mismatched filings, triggers IRS notices, and makes an audit harder than it needs to be. Banks and lenders also use the EIN to tie accounts, credit lines, and tax documents to the right entity.

Business Changes That Require a New EIN

Some changes create a brand-new taxpayer, and a brand-new taxpayer needs a new EIN. The IRS lists the triggers by entity type:1Internal Revenue Service. When to Get a New EIN

  • Sole proprietors need a new EIN if they incorporate, form a partnership, or declare bankruptcy.
  • Corporations need a new EIN when they receive a new charter from the state, create a subsidiary, convert to a partnership or sole proprietorship, or merge with another corporation to form a new entity.
  • Partnerships need a new EIN when they end an existing partnership and start a new one.
  • LLCs need a new EIN when they terminate and reform as a corporation or partnership.

Mergers include a nuance worth knowing. Only the newly created corporation needs a new EIN. If your corporation survives the merger and absorbs the other company, it keeps its existing EIN.1Internal Revenue Service. When to Get a New EIN

Changes That Don’t Require a New EIN

Plenty of changes feel significant but don’t create a new taxpayer. In those cases, your existing EIN carries forward. The IRS says you do not need a new EIN for any of the following:1Internal Revenue Service. When to Get a New EIN

  • Changing your business name or address. Update your records with the IRS, but the EIN stays.
  • Electing S corporation status. A corporation that elects to be taxed as an S corp keeps its existing EIN.
  • Changing an LLC’s tax classification, such as moving from partnership taxation to S corp taxation, or converting a partnership to an LLC classified as a partnership.
  • Partnership ownership changes that do not terminate the partnership itself.
  • Corporate reorganizations that only change identity or location at the state level without changing the underlying business structure.

The pattern is straightforward. If the same legal taxpayer continues to exist after the change, the EIN survives. If the change ends one entity and creates another, you need a new number.

How to Get an Additional EIN

Applying for an EIN is free. The IRS does not charge anything to issue one.5Internal Revenue Service. Employer Identification Number Be wary of third-party sites that charge fees for what the IRS provides at no cost. The FTC has warned consumers about sites that impersonate or falsely suggest an association with the IRS to collect unnecessary fees for EIN applications.6Federal Trade Commission. Looking for an Employer Identification Number (EIN)? The FTC Warns Businesses and Consumers to Watch Out for IRS Imposters

The IRS online EIN application is the fastest route. It validates your information in real time and issues the EIN immediately. The system is open Monday through Friday from 6:00 a.m. to 1:00 a.m. the next day, Saturdays from 6:00 a.m. to 9:00 p.m., and Sundays from 6:00 p.m. to midnight, all Eastern Time.7Internal Revenue Service. Get an Employer Identification Number

One rule matters if you’re forming several entities at once: the IRS limits the online system to one EIN per responsible party per day. If you’re setting up multiple businesses on the same day, you’ll need to space out the online applications or use a different method for the extras.7Internal Revenue Service. Get an Employer Identification Number

You can also fax a completed Form SS-4 and generally receive the EIN within four business days, or mail the form and wait roughly four weeks. Either way, the form asks for the entity’s legal name, any trade names, the type of entity, the reason for applying, and the highest number of employees expected in the next 12 months. You’ll also identify a “responsible party,” the person who ultimately owns or controls the entity, and give that person’s SSN, ITIN, or existing EIN.8Internal Revenue Service. Instructions for Form SS-4 (12/2025)

State Tax IDs Are Separate

A federal EIN doesn’t cover state-level obligations. Most states require businesses to register for a separate state tax identification number, especially if you have employees, collect sales tax, or owe excise or franchise taxes. These IDs come from your state’s department of revenue and serve a different function than your federal EIN. If you operate separate legal entities, each one will likely need its own state tax ID on top of its own federal EIN, and the process and fees vary by state.