On December 7, CME Group halted trading for more than 10 hours after a cooling system breakdown at CyrusOne’s Illinois data center, caused by improper drainage that led to freezing and overheating during initial repairs. The outage disrupted multiple markets, including crypto futures, and exposed vulnerabilities in CME’s reliance on a single facility. The event follows an earlier incident where BrokerTec EU markets resumed after a similar cooling failure, but other CME Group markets stayed paused until repairs concluded.