Co-reinsurance

Co-reinsurance is the mechanism by which one layer is written by several reinsurers, each for a set percentage, on a single contract and on identical terms. Liability is several and not joint: one party's default shifts nothing onto the others, and the cedant alone carries the defaulter's share. The problem it solves is twofold. For the reinsurer, it caps exposure to a given cedant and peril, allowing diversification rather than concentration. For the cedant, it opens access to capacity no single market would supply, and it spreads credit risk across several signatures. The point to watch is precisely the absence of joint liability, often misunderstood: a cedant announcing a layer placed one hundred percent with fifteen markets must check each one's rating, because every share is a separate credit exposure, and an eight percent line carried by a fragile market is an eight percent hole waiting to open.

An 80 million euro layer is placed in 2026 with sixteen reinsurers, shares from 3 to 14 percent. In 2028 one of them, carrying 6 percent, is wound up while owing 4.8 million on a loss. The other fifteen pay their 94 percent with no top-up. The cedant recovers 31 percent of its claim in the liquidation, 1.49 million, and takes a net loss of 3.31 million.

Co-reinsurance, Souscription en parts, Partage de tranche, Subscription market