Inuring reinsurance

Reinsurance is said to inure to the benefit of another treaty when it applies first and its recoveries are deducted from the loss presented to that other treaty. The order of application is not obvious and must be stipulated, because it changes a program's economics entirely: if a quota share inures to a catastrophe layer, the layer sees losses already reduced by the ceded share, hence a smaller exposure and a lower price; if the order is reversed, the quota share benefits from the layer and it is the quota share that costs less. The problem it solves is the coherence of a program made of several overlapping treaties: with no declared order, each reinsurer can argue the other responds first, and the cedant is left carrying a gap nobody acknowledges. The order clause appears in well drafted treaties and must be reread whenever the structure changes, since a treaty added mid-program alters the exposure of every treaty sitting after it.

A cedant holds a 30 percent quota share and a 40 million xs 20 catastrophe layer in 2026. An event costs 90 million gross. The quota share inuring first, it absorbs 27 million and the layer sees only 63 million, of which it pays 40. Were the order reversed, the layer would pay 40 on 90, and the quota share 30 percent of the remaining 50 million, that is 15 million, leaving the cedant 35 net instead of 23.

Inuring reinsurance, Réassurance sous-jacente, Inuring to the benefit, Traité prioritaire