Section 66D. A domestic life company may invest in, acquire and hold fifty-one percent or more of the capital stock of any corporation as a subsidiary which is: a corporation providing investment advisory or management services; a corporation providing sales services to an investment company; a real property holding, developing, managing or leasing corporation; a data processing or computer service corporation; or a corporation whose business has been approved by the commissioner as complementary or supplementary to the business of a domestic life company; provided, however, that such percentage of capital stock may with the approval of the commissioner be less than fifty-one, excepting (1) an insurance company authorized to transact in the commonwealth the business set forth in the First, Second, Third, Fourth, Fifth or Eighth clause of section forty-seven, and (2) a corporation licensed by the commonwealth as an insurance agent or insurance broker for any business set forth in said clauses.