Using a unique proprietary dataset of primary insurers and reinsurers, we analyze the structure of the reinsurance market. The dataset, which spans six years, contains the quotes for different reinsurance layers, for different clients, for different treaties, and for different lines of business. This is the first study that documents the actual structure of the global reinsurance market using actual quotes, and not only the wining quote, for a large number of layers of a large number of reinsurance treaties.