Mass. Gen. Laws ch. 175, § 10

The commissioner shall determine the liability of a company other than a life company or a health maintenance organization as defined in chapter 175G, upon its contracts of insurance. The determination shall be prepared in accordance with accounting practices and procedures prescribed or allowed by the commissioner. The commissioner shall require that they be maintained and prepared in accordance with the Annual Statement Instructions and Accounting Practices and Procedures Manual adopted by the National Association of Insurance Commissioners unless further modified by the commissioner as he considers appropriate.