220 ILCS 5/5-109
Each public utility in the State, other than a commercial mobile radio service provider, shall each year furnish to the Commission, in such form as the Commission shall require, annual reports as to all the items mentioned in the preceding Sections of this Article, and in addition such other items, whether of a nature similar to those therein enumerated or otherwise, as the Commission may prescribe. Such annual reports shall contain all the required information for the period of 12 months ending on June 30 in each year, or ending on December 31 in each year, as the Commission may by order prescribe for each class of public utilities, except commercial mobile radio service providers, and shall be filed with the Commission at its office in Springfield within 3 months after the close of the year for which the report is made. The Commission shall have authority to require any public utility to file monthly reports of earnings and expenses of such utility, and to file other periodical or special, or both periodical and special reports concerning any matter about which the Commission is authorized by law to keep itself informed. All reports shall be under oath.
When any report is erroneous or defective or appears to the Commission to be erroneous or defective, the Commission may notify the public utility to amend such report within 30 days, and before or after the termination of such period the Commission may examine the officers, agents, or employees, and books, records, accounts, vouchers, plant, equipment and property of such public utility, and correct such items in the report as upon such examination the Commission may find defective or erroneous.
All reports made to the Commission by any public utility and the contents thereof shall be open to public inspection, unless otherwise ordered by the Commission. Such reports shall be preserved in the office of the Commission.
Any public utility which fails to make and file any report called for by the Commission within the time specified; or to make specific answer to any question propounded by the Commission within 30 days from the time it is lawfully required to do so, or within such further time, not to exceed 90 days, as may in its discretion be allowed by the Commission, shall forfeit up to $100 for each and every day it may so be in default if the utility collects less than $100,000 annually in gross revenue; and if the utility collects $100,000 or more annually in gross revenue, it shall forfeit $1,000 per day for each and every day it is in default.
Any person who willfully makes any false return or report to the Commission or to any member, officer, or employee thereof, any person who willfully, in a return or report, withholds or fails to provide material information to which the Commission is entitled under this Act and which information is either required to be filed by statute, rule, regulation, order, or decision of the Commission or has been requested by the Commission, and any person who willfully aids or abets such person shall be guilty of a Class A misdemeanor.
220 ILCS 5/5-109