There are two types of treaties 1. Proportional Under proportional reinsurance, one or more reinsurers take a stated percentage share of each policy that an insurer writes. This means that the reinsurer will receive that stated percentage of the premiums and will pay the same percentage of claims. In addition, the reinsurer will allow a ceding commission to the insurer to cover the costs incurred by the insurer (marketing, underwriting, claims etc.).