Federal Registration Requirements. You may need to obtain a federal employer identification number (EIN) to identify your business entity. To find out if you are required to obtain an EIN, take the IRS test. Every partnership, corporation, and S-Corporation requires an EIN. If you are a sole proprietor with no employees, and you do not file excise or pension tax returns, you do not need an EIN. Instead, you use your social security number for filing federal taxes.
State Registration Requirements. All persons that engage in the sale of tangible personal property at retail, or supplier or serviceman1, must register with the Illinois Department of Revenue before conducting business or hiring any employees in Illinois. This includes sole proprietorships (86 IAC 130.701).
You can register online through the Illinois Business Gateway, or by submitting a form. The business registration must be displayed in a prominent location at the business site.
If you hire any employees, you must register the business with the Illinois Department of Economic Security. Details can be found on the labor and employment issues page.
1 A serviceman is "any person who sells tangible personal property as an incident to sale of service (86 IAC 140.120).
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