Does an Illinois sole proprietor need an EIN?

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 20, 2026 · Last updated Aug 20, 2026

Not unless you have employees or owe certain excise taxes; you may use your Social Security number. Many sole proprietors still get the free IRS EIN to open a business bank account and avoid sharing their SSN.

Quick facts

State formation filing: None – a sole proprietorship is automatic when you do business
Liability: Unlimited – your personal assets are exposed to business debts
Trade name (DBA): Assumed Business Name filed with the county clerk
Federal tax: Schedule C; 15.3% self-employment tax on net profit
Illinois income tax: Flat 4.95% on net income
EIN: Optional unless you have employees or excise-tax duties

The same question in every other state

This requirement is set at state level, so the answer changes when you cross a state line. Below is how 25 other states answer the same question, each linked to the page that cites the agency it came from. The full breakdown is on How to Form an LLC.

State	Answer
Arkansas	Not always. A sole proprietor with no employees can use a Social Security number.
Georgia	Only if you hire employees or file certain excise or pension returns. Otherwise you can use your Social Security number, though many owners get a free EIN to open a bank account and protect their SSN.
Hawaii	A sole proprietor with no employees can use a Social Security number. You must obtain a free EIN from the IRS if you hire employees, file certain excise or pension returns, or a bank requires one for a business account.
Indiana	Not always. A sole proprietor with no employees can use a Social Security number.
Kansas	Not always. A sole proprietor with no employees may use a Social Security number on federal filings.
Maryland	Not always. You can use your Social Security number if you have no employees, but you must get a free EIN if you hire employees or file certain taxes.
Minnesota	Only if the proprietorship has employees, files certain excise returns, or maintains a qualified retirement plan. Otherwise the owner may use a Social Security number.
Missouri	Not usually. A sole proprietor with no employees and no excise tax obligations can use a Social Security number.
Montana	Not always. A sole proprietor with no employees can generally use a Social Security number for federal tax purposes.
Nevada	Not always. A sole proprietor with no employees can use their Social Security number, but must get a free EIN to hire employees or file certain excise or pension returns.
New Hampshire	Not usually. A sole proprietor with no employees can use a Social Security number.
New Jersey	You need a federal EIN if you have employees or file certain excise or pension returns. A sole proprietor with no employees can often use a Social Security number, but many get a free EIN from the IRS to open a bank account and avoid sharing their SSN.
New Mexico	Only if you hire employees or file certain excise or pension returns. Otherwise you can use your Social Security number, though many owners get a free EIN to open a bank account and protect their SSN.
New York	Not necessarily. With no employees you may use your Social Security number for federal filings.
North Carolina	Only if the business has employees, files certain excise returns, or maintains a qualified retirement plan. Otherwise the owner may use a Social Security number.
Ohio	Not always. A sole proprietor with no employees can use their Social Security number.
Pennsylvania	A sole proprietor with no employees can use a Social Security number, but an EIN is required to hire employees or file certain excise tax returns and is often needed to open a business bank account. The EIN is issued free by the IRS using Form SS-4.
South Carolina	Not usually. A sole proprietor with no employees can use a Social Security number.
Utah	Not unless you have employees, file employment or excise tax returns, or set up certain retirement plans. Otherwise the owner's Social Security number can serve as the tax identifier.
Vermont	Not always. A sole proprietor with no employees may use a Social Security number, but an EIN is required once you hire, and many banks and clients prefer it because it keeps your SSN off paperwork.
Virginia	Not always. Without employees you may use your Social Security number for federal filings.
Washington	Not usually. A sole proprietor with no employees can use a Social Security number.
West Virginia	Not always. With no employees you may use your Social Security number on federal filings.
Wisconsin	Not always. A sole proprietor with no employees can generally use a Social Security number for federal tax purposes.
Wyoming	Not usually. A sole proprietor with no employees can use a Social Security number.

Full context for Illinois

This page answers one question. The complete Illinois guide -- covering the surrounding requirements, the forms, the agency, and what happens if you get it wrong -- is at Sole Proprietorship in Illinois (2026).

Sources

LegalGlass provides general information for educational purposes and is not a law firm or a substitute for advice from a licensed attorney or tax professional. Laws and fees change; verify current requirements with the relevant government agency before acting.