Section 11. Every telephone or telegraph company doing business in the commonwealth shall annually, on or before March thirty-first or such subsequent date as the department of telecommunications and cable, for good cause shown in any case, may fix, file with said department a report of its doings for the year ending December thirty-first preceding, which report shall be in such detail as the department prescribes, and shall be called the ”Annual Return.” Such return shall be sworn to by the treasurer and by the chief accounting officer of such company, and shall include a statement of its business, receipts and expenditures within the commonwealth during the year, its dividends paid out and declared, the amount of its authorized capital and its indebtedness and financial condition. The word ”company” in this section and in section 12 shall include every person, partnership, association, corporation and municipal lighting plant or cooperative authorized pursuant to section 47E of chapter 164 to engage in the business of the transmission of intelligence by electricity.