These guidelines are provided for assistance only. The Department of Human Services is not responsible for incorrect information, submission, changes, etc., on a vendor's W-9 tax form.


  1. The W-9 is a legal document; information must match your IRS records. If you are not sure how you are listed with IRS, you may call:
    • Tax Exempt: 1-877-829-5500
    • Small Business: 1-800-829-4933
    • All Others: 1-800-829-1040
    • TDD Only: 1-800-325-0778
  2. Illinois Office of the Comptroller (IOC) will not use a W-9 that is not legible.
  3. Individual/Sole Proprietor: Always enter the name of a person on the TOP line. If there is a doing business as (dba) or business name, this goes on the 2nd line. May use Social Security Number (SSN) or Employer Identification Number (EIN) also known as FEIN. Check 'Individual/Sole Proprietor' box for tax classification.
  4. Corporation: Always enter complete corporation name as listed with IRS on TOP line. Use EIN only. Check 'Corporation' box for tax classification.
  5. Partnership: Always enter complete partnership name as listed with IRS on TOP line. Use EIN only. Check 'Partnership' box for tax classification.
  6. Limited Liability Company: Must check the box for limited liability company and must enter tax classification (C, S, or P) on the dotted line provided. Do not check any boxes above. The IOC will not accept a W-9 with more than one status box marked.
    1. C= Place corporation name on top line. Vendors must include a copy of IRS acceptance letter. This letter states IRS has accepted the vendor's request to be considered a corporation. The word ACCEPT is in the first paragraph. Do not send the IRS FEIN ID letter. To obtain a copy of the IRS Acceptance Letter, call: 1-800-829-0115. Under Part 1, use EIN only not an SSN.
    2. S = Place corporation name on top line. Vendors must include a copy of IRS acceptance letter. This letter states IRS has accepted the vendor's request to be considered a corporation. The word ACCEPT is in the first paragraph. Do not send the IRS FEIN ID letter. To obtain a copy of the IRS Acceptance Letter, call: 1-800-829-0115. Under Part 1, use EIN only not an SSN.
    3. P= Place partnership name on top line. Second line should be blank. Send a copy of the IRS FEIN ID letter. To obtain a copy of the IRS FEIN ID Letter, call: 1-800-829-0115. Do not send IRS acceptance letter. Under Part 1, use EIN only.
  7. Single Member LLC that is a disregarded entity owned by an individual: Always enter the owner's legal name on the top line.On the 2nd line for Business Name enter the name of the LLC.  On the 3rd line check the box for Individual/sole proprietor or single-member LLC.  On Part I Taxpayer Identification Number (TIN) enter the Social Security Number of the owner or the Federal Taxpayer Identification Number (ONLY if the owner has one assigned to his/her name). DO NOT enter the Federal Employee Identification Number assigned to the LLC. Attach a copy of the IRS/EIN Assignment Letter (SS-4 / CP 575) with the W-9.  If you need to  obtain a copy of the IRS/EIN Assignment letter, please call 800-829-0115.  NOTE:  A Single Member LLC is required to use the tax identification of the owner when conducting business with the state of Illinois.
  8. Single Member LLC that is a disregarded entity owned by another business entity:  Always enter on the top line the name of the business entity that owns the LLC.  On the 2nd line for the Business Name/disregarded entity name, enter the name of the LLC. On the 3rd line, check the appropriate federal tax classification for the business entity that owns the LLC.  On Part I Taxpayer Identification Number (TIN) enter the owning business entity's Federal tax identification number. DO NOT enter the Federal Employee Identification Number assigned to the LLC. Attach a copy of the IRS Acceptance Letter accepting the federal tax classification of the business entity that owns the LLC and a copy of the IRS/EIN Assignment Letter (SS-4 / CP 575) of the LLC with the W-9.  If you need to  obtain a copy of the IRS/EIN Assignment letter, please call 800-829-0115.  NOTE:  A Single Member LLC is required to use the tax identification of the business entity that owns the LLC when conducting business with the state of Illinois.
  9. Legal Status 'Other': Put Federal Tax Exempt or Government as explanation. If tax exempt, submit IRS proof of not-for-profit status along with the W-9.