Mass. Gen. Laws ch. 182, § 7: Investigation or examination of trusts owning or holding stock in certain public utilities; access to information

Section 7. The department may by its members or duly authorized employees investigate and examine the books, accounts, contracts, records and memoranda of the trustees of any association or trust, who own or hold the capital stock or any part thereof of a railroad, street railway, electric railroad or elevated railway corporation, gas, electric or water company, or corporation engaged in the common carriage of passengers by motor vehicle, and may require said trustees to furnish such reports and information as the department shall from time to time direct with respect to the relations and dealings between such trustees and any such corporation or company.