To know what type of business you have, look at the formation paperwork you filed with your state when you started. If you never filed anything, you are a sole proprietor by default (or a general partnership if you started the business with someone else). If you did file, the document itself names the entity: Articles of Organization means an LLC, Articles of Incorporation means a corporation, and a Certificate of Limited Partnership means a limited partnership. Everything else — your tax return form, your EIN letter, your bank records — is confirmation, and sometimes those confirmations disagree with each other in ways worth understanding.
Start With Your Formation Documents
The formation document is the definitive source. It is the piece of paper that created the entity, and its title tells you what the entity is.
Articles of Organization create a Limited Liability Company. The document lists the organizers, the registered agent, and whether the LLC is member-managed or manager-managed. The legal name in the filing has to include a designation such as “LLC,” “L.L.C.,” or “Limited Liability Company.”1Cornell Law Institute. Articles of Organization
Articles of Incorporation create a corporation. The filing sets out the number of authorized shares and the company’s stated purpose, and the legal name has to include “Corporation,” “Incorporated,” “Corp.,” or “Inc.”
A Certificate of Limited Partnership creates a limited partnership, which separates general partners (who run the business and carry full personal liability) from limited partners (who put in money and stay out of operations).
If You Never Filed Anything
No filing is itself a classification. A person running a business alone without forming an entity is a sole proprietor. The IRS treats you and the business as the same taxpayer, and your personal assets are exposed to business creditors.2Internal Revenue Service. Sole Proprietorships
Two or more people carrying on a business together for profit, without filing formation documents, are a general partnership by default. The Uniform Partnership Act, adopted in some form by every state, defines the relationship that way.3UKnowledge. Partnership–Tests and Indicia of the Relation–Co-Owners as Partners Every general partner shares management authority and is personally liable for the full amount of any business debt. If your partner takes on $200,000 in business obligations, a creditor can pursue you for the whole $200,000, not just half.
Confirm Through Your State’s Business Database
If you filed formation documents but can’t find your copies, or you want independent confirmation, your state’s Secretary of State runs a searchable online database of every registered entity. Enter the business name and the results show the entity type, formation date, registered agent, and current status.
Read the status field carefully. “Active” or “In Good Standing” means the entity is current on its filings. “Suspended,” “Forfeited,” or “Dissolved” means it isn’t, and a dissolved entity may have lost the legal protections it was formed to provide. If the listing is active and the entity type matches what you thought you were, that’s your confirmation.
Most state databases also let you download the original formation documents for a small fee, and you can request a certificate of good standing (in some states called a certificate of legal existence) when a bank or an out-of-state deal asks for formal verification.
Check Your Federal Tax Records
Federal records tell you how the business is classified for tax purposes. Keep that phrase in mind: tax classification is not always the same thing as legal structure, and the difference trips people up constantly.
Your EIN Confirmation Letter
When you applied for an Employer Identification Number on Form SS-4, you checked a box for entity type. The IRS lists sole proprietor, partnership, corporation, personal service corporation, and other categories on the form.4Internal Revenue Service. Instructions for Form SS-4 (Rev. December 2025) The confirmation letter you received back, called CP 575, records that selection. Banks routinely ask for it to match the tax ID to the business structure.
If you applied online, you may have saved the PDF at the end of the session. If you applied by mail, the letter arrived within eight to ten weeks. Lost it? Your bank probably has a copy from when you opened the business account.
The Tax Form You File Each Year
The form your business files is itself a declaration of type. Pull last year’s return and check the form number printed at the top.
- Schedule C attached to Form 1040 means you are filing as a sole proprietor.5Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship)
- Form 1065 means the business is filing as a partnership. Multi-member LLCs default to this treatment.6Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income
- Form 1120 means the business is filing as a C corporation.7Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return
- Form 1120-S means the business is filing as an S corporation.
If your records are genuinely gone, the IRS can send an entity transcript that shows the EIN, filing requirements, and whether an LLC is classified as single-member or multi-member. Request it through your IRS business tax account, by mail with Form 4506-T, or by calling the Business and Specialty Tax Line.8Internal Revenue Service. Get a Business Tax Transcript
Why Your Tax Form Might Not Match Your Legal Structure
This is the piece that catches people out. Your legal structure comes from your state formation documents. Your tax classification comes from what you elected with the IRS. For LLCs, those two answers often diverge.
By default, a single-member LLC is a “disregarded entity” for federal tax purposes, meaning the IRS ignores the LLC and taxes the owner as a sole proprietor. A multi-member LLC defaults to partnership taxation.9Internal Revenue Service. Limited Liability Company (LLC) But an LLC can elect a different tax treatment:
- Form 8832 lets an LLC elect to be taxed as a corporation instead of using its default classification.10Internal Revenue Service. About Form 8832, Entity Classification Election
- Form 2553 lets an LLC (or a corporation) elect S corporation tax treatment. When the IRS approves the election, it sends a CP261 notice.11Internal Revenue Service. Instructions for Form 2553 (Rev. December 2020)12Internal Revenue Service. Understanding Your CP261 Notice
Here is what this looks like in practice. Your LLC filed Form 2553, so your tax returns are on Form 1120-S. You are still an LLC under state law. You did not become a corporation. Your operating agreement, your state database listing, and your liability protections all still reflect an LLC. When a bank or landlord asks what type of business you have, the accurate answer is “LLC taxed as an S corporation,” not “S corporation.” Signing a contract as a corporation when the state has you registered as an LLC is the kind of mismatch that delays loan closings and gives counterparties leverage to argue a contract was signed by a nonexistent entity.
When the Records Disagree
The safest check is to cross-reference at least two sources. If your formation document says LLC, the state database shows an active LLC, and your tax return is Form 1065 or Schedule C or 1120-S, all of that is consistent with an LLC (with the tax form telling you which election, if any, is in place).
If two sources disagree, the state filing controls the legal question and the IRS filing controls the tax question. A state database showing “corporation” while you have been filing Schedule C is a real problem and needs to be sorted out before you sign your next lease, apply for financing, or file your next return. A local DBA or city business license filing that lists the wrong entity type is a lower-stakes fix, but worth updating so public records line up.
One thing to know about the state side: registered entities have ongoing filing obligations, usually an annual or biennial report and a fee. If those lapse, the state can administratively dissolve the entity, and a dissolved LLC or corporation may no longer give you the liability shield you formed it to get. Checking the status field in your state’s database once a year takes two minutes.