To protect themselves from catastrophic losses, insurance companies buy insurance, in the same way that people do. These contracts are called reinsurance agreements, and come in two main forms: proportional and nonproportional contracts. In proportional reinsurance contracts, a reinsurer agrees to repay a fixed proportion of losses incurred by the primary insurer. The simplicity of the agreement makes these types of contracts inexpensive and easy to administer. Therefore, they can be ideal risk-management tools for small insurance companies.