(735 ILCS 5/18-101) (from Ch. 110, par. 18-101)
    Sec. 18-101. Grounds. A proceeding in quo warranto may be brought in case:
    (1) Any person usurps, intrudes into, or unlawfully holds or executes any office, or franchise, or any office in any corporation created by authority of this State;
    (2) Any person holds or claims to hold or exercise any privilege, exemption or license which has been improperly or without warrant of law issued or granted by any officer, board, commissioner, court, or other person or persons authorized or empowered by law to grant or issue such privilege, exemption or license;
    (3) Any public officer has done, or allowed any act which by the provisions of law, works a forfeiture of his or her office;
    (4) Any association or number of persons act within this State as a corporation without being legally incorporated;
    (5) Any corporation does or omits to do any act which amounts to a surrender or forfeiture of its rights and privileges as a corporation, or exercises powers not conferred by law;
    (6) Any railroad company doing business in this State charges an extortionate rate for the transportation of any freight or passenger, or makes any unjust discrimination in the rate of freight or passenger tariff over or upon its railroad.
(Source: P.A. 82-280.)