“What’s Natural About the Expiration of In-Force Policies When a Reinsurance Contract Terminates?,” Expert Commentary section of the Internet Web site of the International Risk Management Institute (www.IRMI.com) 

Reinsurance contracts often have termination provisions with runoff and/or cutoff language to inform the parties where the reinsurer's obligation ends on losses arising from in-force insurance policies reinsured at the time of the reinsurance contract's termination or expiration. This is because claims often arise well after the reinsurance contracts have expired, and the contracting parties need to know who will be responsible for those ongoing risks.