Indiana Code Title 6. Taxation § 6-1.1-8-21

Sec. 21.  The department of local government finance may ask a public utility company to provide the department with copies of any reports which the company has filed with a state or federal agency if:

If the department of local government finance makes such a request, the company shall provide the department with copies of the reports.  The department of local government finance may also inspect the original reports filed by the company regardless of whether or not the department has obtained copies of the reports from the company.  In addition, the department of local government finance may inspect a public utility company's property, books, and records.