Section 47A. A domestic insurance company may, notwithstanding any limitation otherwise applicable, and provided it maintains books and records which account for such business, engage directly in any of the following businesses: (a) rendering investment advice; (b) rendering services related to the functions involved in the operation of its insurance business including, but not limited to, actuarial, loss prevention, safety engineering, data processing, accounting, claims, appraisal and collection services; (c) acting as administrative agent for a government instrumentality which is performing an insurance function or is responsible for a health or welfare program; (d) any other business activity reasonably complementary or supplementary to its insurance business; either to the extent necessarily or properly incidental to the insurance business the insurer is authorized to do in this commonwealth or to the extent approved by the commissioner and subject to any limitations he may prescribe for the protection of the interests of the policyholders of the insurer after taking into account the effect of such business on the insurer's existing insurance business and its surplus, the proposed allocation of the estimated cost of such business and the risks inherent in such business as well as the relative advantages to the insurer and its policyholders of conducting such business directly instead of through a subsidiary; provided, however, the foregoing authorized direct businesses shall not include the business of acting in this commonwealth for another insurer as insurance agent, insurance broker, special insurance broker, or public insurance adjuster.