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New company registration in Illinois

Illinois Tax Agencies

  • Illinois Department of Revenue - income tax withholding
  • Illinois Department of Employment Security (IDES) - unemployment tax

Register a new company

Income tax withholding and unemployment tax

  1. Register for both income tax withholding and unemployment tax through the Illinois Department of Revenue website. Click registration and complete.
  2. For Income Tax Withholding, you’ll receive a taxpayer ID which will consist of your Federal EIN plus a Sequence Number (usually -000, but can sometimes be -001).
    • Most new employers in Illinois will have a -000 sequence number.
    • You will be required to fill out the correct Sequence Number.
    • If you are unsure about your sequence number, please reach out to the department at (800) 732-8866.
  3. For Unemployment Tax, most companies are liable for state unemployment if they pay at least $1,500 in wages in a single calendar quarter or employed one or more persons for 20 weeks in a given calendar year. If considered liable, you'll instantly be issued an Unemployment Account Number in the format of XXXXXXX-X. The last digit of your Unemployment number is called the check digit and the department will often omit it from correspondence.
    • Gusto only requires the first seven digits of the Unemployment number, do not include the eighth digit (if present) when entering the number in your account.
    • If your Unemployment number is less than seven digits, add leading zeros to create a seven digit number when entering your information in Gusto.
      • New employers will always have seven digit numbers, and they will typically start with a "5."
  4. UI tax rate: The unemployment rate for new employers varies by industry and includes the Fund Builder Rate. When entering your unemployment rate in Gusto, include the Fund Builder Rate in addition to your assigned experience rate. Click here to view state-by-state new employer rates and wage bases.
  5. Monthly wage reporting requirement: Employers with more than 25 employees in Illinois are required to file monthly wage reports to Illinois Department of Employment Security.
    • Gusto files this monthly report on behalf of all of our customers regardless of the number of employees you have.

Third party access to Illinois Department of Revenue 

You must grant Gusto access to your MyTax Illinois account in order for us to file and pay your Illinois withholding taxes. 

  1. Login to your MyTax Illinois account
  2. Click on Settings in the top-right hand menu.
  3. Select Manage Third Party Access.
  4. Under "Third Party Access" make sure the:
    • "Allow" setting is set to Yes. 
    • "Default access" is set to Third Party.
    • "Default account access" is set to Full Access. 

To change these settings, click the blue link to toggle to the designation above.

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