When you apply for an EIN, Form SS-4 asks you to check exactly one box describing your entity type, and that single choice tells the IRS which tax returns to expect from you for the life of the number. The EIN business categories on Line 9a are: sole proprietor, partnership, corporation, personal service corporation, estate, trust, plan administrator, church or church-controlled organization, other nonprofit organization, state/local government, federal government, Indian tribal governments, farmers’ cooperative, REMIC, and a catch-all “Other.” Pick the one that matches how your entity will actually be taxed, not what it’s called under state law.
Getting the category right the first time is worth the effort. A mismatch between your EIN record and the returns you file generates automated compliance notices, and correcting a wrong selection is a separate process from applying — you cannot just file another SS-4 on top of the first.
The Four Commercial Categories
Most applicants belong in one of four groups. Each maps to a different return.
Sole Proprietor
A sole proprietorship is you and your business as the same legal entity. Income and expenses go on Schedule C attached to your personal Form 1040.1Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) Many sole proprietors don’t actually need an EIN at all. You only need one if you hire employees, operate a qualified retirement plan, or need to file certain excise tax returns.2Internal Revenue Service. 2025 Instructions for Schedule C (Form 1040) Getting one anyway for banking purposes or to avoid giving vendors your Social Security number is allowed.3Internal Revenue Service. Employer Identification Number
Partnership
A partnership exists whenever two or more people or entities agree to share profits or losses from a business. Every domestic partnership needs its own EIN and files Form 1065, an informational return; the partnership itself generally doesn’t pay income tax. Each partner receives a Schedule K-1 showing their share and reports it on their individual return.4Internal Revenue Service. Instructions for Form 1065 (2025)
Corporation
Corporations are legally separate from their owners, and every corporation needs its own EIN whether or not it has employees. A standard C corporation files Form 1120 and pays corporate income tax on its profits.5Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return An S corporation avoids that entity-level tax by passing income through to shareholders.
S corp status is not a box on the EIN application. You get your EIN as a corporation, then file Form 2553 to elect S corp treatment.6Internal Revenue Service. About Form 2553, Election by a Small Business Corporation A corporation that later elects S corp status keeps its existing EIN.7Internal Revenue Service. When to Get a New EIN
The LLC Question
LLCs cause more confusion here than any other entity type, because “LLC” is a state-level legal designation, not a federal tax classification. The IRS has no LLC category. It taxes your LLC based on how many members it has and any elections you make.
A single-member LLC is treated by default as a disregarded entity, so its income flows onto the owner’s personal Form 1040 just like a sole proprietorship. If the LLC has employees, it must use its own name and EIN for employment tax reporting even though income taxes are reported under the owner’s name and Social Security number.8Internal Revenue Service. Single Member Limited Liability Companies
A multi-member LLC is automatically classified as a partnership. To be taxed as a corporation instead, the LLC files Form 8832, Entity Classification Election.9Internal Revenue Service. About Form 8832, Entity Classification Election An LLC that wants S corp treatment can skip Form 8832; filing Form 2553 alone is treated as an implicit election to be classified as a corporation.10Internal Revenue Service. Form 8832 Entity Classification Election
So the box you check on the EIN application has to reflect the LLC’s intended federal tax treatment: sole proprietor for a default single-member LLC, partnership for a default multi-member LLC, corporation if you plan to elect corporate or S corp taxation.
Fiduciary and Specialized Categories
The remaining categories exist because estates, trusts, retirement plans, and nonprofits each have their own reporting rules that the IRS wants tagged from day one.
Estate
An estate needs its own EIN when it generates more than $600 in annual gross income, which triggers Form 1041.11Internal Revenue Service. File an Estate Tax Income Tax Return Form 1041 covers income the estate’s assets earn after the decedent’s death, such as interest, dividends, or rental income. This is separate from any estate tax filing.
Trust
A non-grantor trust is its own taxable entity, files Form 1041, and reports distributions to beneficiaries on Schedule K-1.12Internal Revenue Service. About Form 1041, U.S. Income Tax Return for Estates and Trusts A grantor trust, where the person who created the trust still controls it, may not need a separate EIN because its income is reported on the grantor’s personal return. The responsible party for a trust EIN is the grantor or trustee.
Plan Administrator
A qualified retirement plan gets its own EIN, separate from the sponsoring employer’s EIN. The plan uses that number on the annual Form 5500 series return, which the IRS, Department of Labor, and Pension Benefit Guaranty Corporation all use to track plan compliance.13Department of Labor. 2025 Instructions for Form 5500 Annual Return/Report of Employee Benefit Plan
Church or Other Nonprofit
The application lists “Church or church-controlled organization” and “Other nonprofit organization” as separate boxes. Selecting the nonprofit category is the first step in a longer process; after receiving the EIN, the organization applies for tax-exempt recognition by filing Form 1023 (or Form 1023-EZ for smaller organizations).14Internal Revenue Service. How to Apply for 501(c)(3) Status Exempt status doesn’t guarantee zero federal tax. Any exempt organization with $1,000 or more in gross income from an unrelated business must file Form 990-T and may owe tax on that income.15Internal Revenue Service. Unrelated Business Income Tax
Government Entities, Cooperatives, and REMICs
State and local governments, federal government agencies, Indian tribal governments, farmers’ cooperatives, and real estate mortgage investment conduits (REMICs) each have their own box. They are less common but follow the same principle: each triggers a specific set of filing obligations tied to that entity type.
Household Employer
This one catches many people off guard. If you pay a nanny, housekeeper, or other household worker more than $3,000 in cash wages during 2026, you owe Social Security and Medicare taxes on those wages and need an EIN to report them. You also trigger federal unemployment tax (FUTA) if you pay total cash wages of $1,000 or more in any calendar quarter to household employees.16Internal Revenue Service. Publication 926 (2026), Household Employer’s Tax Guide Household taxes are reported on Schedule H, and the IRS specifically requires an EIN there rather than your Social Security number.17Internal Revenue Service. Instructions for Schedule H
The Responsible Party Attached to Every Category
Whichever box you check, the application requires you to name a responsible party: the person who owns, controls, or exercises effective control over the entity and manages its funds and assets.18Internal Revenue Service. Responsible Parties and Nominees You provide that person’s Social Security number or ITIN. For a sole proprietor, it’s the owner. For a corporation, typically a principal officer. For a trust, the grantor or trustee.
The IRS limits you to one EIN application per responsible party per day, so multiple entities have to be spread across multiple days.19Internal Revenue Service. Get an Employer Identification Number If the responsible party later changes, the entity must notify the IRS within 60 days by filing Form 8822-B.20Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
Fixing a Wrong Category
If you checked the wrong box — for example, “Corporation” when your multi-member LLC should have been classified as a partnership — you can’t fix it with a second SS-4. The correction depends on the type of error.
For LLCs stuck with the wrong default classification, the fix is Form 8832 with a request for late election relief. Check Box 6 in Part I to request that relief and set the effective date to match your LLC’s formation date so the correction applies retroactively.9Internal Revenue Service. About Form 8832, Entity Classification Election Attach a statement explaining the error, something as simple as “the wrong box was checked during the EIN application; the LLC always intended to be treated as a partnership.” Include your state LLC formation documents and have all members sign. The IRS generally grants this relief when the intent is clear and the mistake was unintentional.
For errors that don’t involve a classification election, such as an estate mistakenly categorized as a trust, you contact the IRS directly, and the correction can take several weeks. During that gap, filing the correct return for your actual entity type is better than filing the wrong return to match a bad EIN record. Keep copies of your correction correspondence; auditors will want to see them if the discrepancy comes up.
When a Category Change Means a New EIN
Some changes are not category corrections at all. They require a brand-new EIN, and applying for one when you should have corrected the old record (or the reverse) creates duplicate files the IRS will eventually flag.7Internal Revenue Service. When to Get a New EIN
- Sole proprietors need a new EIN if they incorporate or form a partnership.
- Corporations need a new EIN if they get a new charter from the secretary of state, become a subsidiary, change to a partnership or sole proprietorship, or merge to create a new corporation.
- Partnerships need a new EIN if they incorporate, end the partnership and begin a new one, or dissolve so one partner takes over as a sole proprietor.
- LLCs need a new EIN if they terminate the existing LLC and form a new corporation or partnership.
Knowing when you don’t need a new one matters just as much. A corporation electing S corp status keeps its existing EIN. An LLC that changes its tax election from partnership to corporation, or vice versa, also keeps its EIN. A state-level conversion that doesn’t change the federal business structure doesn’t trigger a new number, and a partnership that undergoes an ownership change without formally terminating doesn’t either.7Internal Revenue Service. When to Get a New EIN