A proportional reinsurance covering claims only to the extent that they exceed a certain amount or ration, e.g. a liability insurer may reinsure all losses (or a proportion thereof) in excess of £1m, the excess point, up to £2m. Excess of loss has many applications; catastrophe reinsurance, per occurrence reinsurance, per risk reinsurance, aggregate excess of loss, excess of loss ratio. Cover is normally by means of treaty.