An insurance policy is a legal contract between the insurance company (the insurer) and the person(s), business, or entity being insured (the insured). Reading your policy helps you verify that the policy meets your needs and that you understand your and the insurance company's responsibilities if a loss occurs.
Reinsurance companies often use a formal sharing agreement, also known as a treaty agreement. This enables the sharing of risk between the primary insurer and the reinsurer. In this arrangement, the primary insurer cedes a portion of the risk they have underwritten to the reinsurer.