35 ILCS 625/11
All information received by the Department from returns filed under this Act, or from any investigations conducted under this Act, shall be confidential, except for official purposes, and any person who divulges any such information in any manner, except in accordance with a proper judicial order or as otherwise provided by law, shall be guilty of a Class B misdemeanor.
Nothing contained in this Act shall prevent the Director from publishing or making available to the public the names and addresses of taxpayers filing returns under this Act, or from publishing or making available reasonable statistics concerning the operation of the tax wherein the contents of returns are grouped into aggregates in such a way that the information contained in any individual return shall not be disclosed.
Nothing contained in this Act shall prevent the Director from making available to the United States Government or any officer or agency thereof, for exclusively official purposes, information received by the Department in the administration of this Act.
The furnishing upon request of the Auditor General, or his authorized agents, for official use, of returns filed and information related thereto under this Act is deemed to be an official purpose within the meaning of this Section.
The Director may make available to any State agency, including the Illinois Supreme Court, which licenses persons to engage in any occupation, information that a person licensed by such agency has failed to file returns under this Act or pay the tax, penalty and interest shown therein, or has failed to pay any final assessment of tax, penalty or interest due under this Act. An assessment is final when all proceedings in court for review of such assessment have terminated or the time for the taking thereof has expired without such proceedings being instituted.
Nothing contained in this Act shall prevent the Director from divulging information to any person pursuant to a request or authorization made by the taxpayer or by an authorized representative of the taxpayer.
35 ILCS 625/11