Surplus share reinsurance and quota reinsurance are two types of agreement between an insurer and a reinsurer that define the responsibilities of each party. In a surplus share treaty, the primary insurer retains the liabilities of a contract up to a specific amount. The remainder is passed along to a reinsurer. A quota share treaty is essentially the reverse. The primary insurer passes along the responsibility for risks to a reinsurer, up to a certain limit. The primary insurer is responsible for losses exceeding that amount.