All life insurance companies and property insurance companies under the supervision of the American Institute of Insurance Commissioners consist of 1760 life insurance companies and 2,707 property insurance companies. Most of them belong to group companies, because it is easy for group companies to share the same financial strategy and the same investment department. Group/non-affiliated company is composed of 1423 group and non-affiliated single company.
Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.