(a) An insurance company licensed in this State, or a hospital or medical service corporation authorized to do business in this State, either directly or through a subsidiary or affiliate, may organize and operate a health maintenance organization under the provisions of this chapter. Notwithstanding any other law to the contrary, any two or more insurance companies, hospital or medical service corporations, or subsidiaries or affiliates thereof, may jointly organize and operate a health maintenance organization. The business of insurance is deemed to include the providing of health care by a health maintenance organization owned or operated by an insurer or a subsidiary thereof.