Section 1B. Any corporation conducting the business referred to in section one of chapter one hundred and seventy-two A, whether or not such corporation shall have been authorized to do the business of a banking company under said chapter, shall be subject to the supervision of the commissioner and, except as otherwise provided in this section, the provisions of sections four to eight, inclusive, and ten to fourteen, inclusive, of said chapter, shall apply to such corporation. Any such corporation shall carry on only such business and shall make only such investments as are authorized by said chapter; provided, that in the case of any corporation subject to section seven A thereof, the holding and disposition of assets not authorized as investments by section seven thereof shall be governed by said section seven A. The rates of interest charged on loans coming within the limitations of section ninety-six of chapter one hundred and forty by any corporation conducting the business hereinbefore referred to shall not exceed the rates established by the commissioner pursuant to section one hundred of chapter one hundred and forty, but whenever any such corporation shall have been authorized to do the business of a banking company under said chapter one hundred and seventy-two A rates of interest authorized by section nine of said chapter shall apply. No such corporation incorporated after January first, nineteen hundred and thirty-eight shall transact, in this commonwealth, the business referred to in section one of said chapter until it shall have received a certificate from the board of bank incorporation under section two of said chapter.