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IDOR-50-L-1M - Tax Location Verification

When and why are these letters and lists sent?

We produce and mail on a monthly basis a IDOR-50-L-1M, Tax Location Verification, to notify you of new businesses, changes to existing registration of businesses, and discontinuation of businesses within your taxing jurisdiction. If there has been no activity to accounts within your taxing jurisdiction, we will not produce a IDOR-50-L-1M.

What information is provided to you on the IDOR-50-L-1M?

IDOR-50-L-1M and its attachments will list the business name, doing business as (DBA) name (if applicable), Illinois Business Tax (IBT) number, address, and site number for
  • new registrations, reinstatements and corrections; and
  • discontinued accounts

NOTE: Illinois Business Tax (IBT) numbers eventually will be replaced by Account IDs when that tax is included in the new system. At the end of the four-year transition period, use of the term “IBT” will be discontinued.

What is your responsibility in reviewing the IDOR-50-L-1M?

You should verify that the businesses listed are located in your taxing jurisdiction, make any comments that further describe the situation, and return the corrections to us.

Your prompt verification of the information in this letter is critical to assure that the allocation of local sales tax dollars is accurate. Please notify us as soon as possible if you note any discrepancy when you review these lists.

Now you can do this on-line, try our Tax Location Verification application.

Where do you send verification notices and questions?

Verification notices, as well as questions concerning these letters and accompanying attachments, should be directed to:

PO BOX 19030
Telephone: 217 785-3707