Full Breakdown
Major Trading Outage at Chicago Mercantile Exchange Due to Cooling Failure
11/30/2025, 11:26:23 AM
Overview of the Incident
On November 28, 2025, the Chicago Mercantile Exchange (CME) experienced a significant trading disruption lasting approximately ten hours due to a cooling system failure at the CyrusOne CHI1 data center in Aurora, Illinois. This incident halted trading across multiple asset classes, including commodities, foreign exchange, and equity indices, affecting markets globally, particularly in Asia and Europe.
Timeline of Events
The outage began late on November 27, 2025, around 20:40 CT, when CME first flagged its Globex futures and options markets as halted due to a technical issue. By early morning on November 28, trading in key benchmarks such as S&P 500 futures, gold, and U.S. Treasury futures was frozen, with no updates on pricing reported by 5:30 a.m. ET. CME began partially restoring operations by reopening its EBS forex platform around noon London time, but many futures markets remained offline.
Impact on Global Markets
The disruption had widespread implications, freezing price discovery for critical commodities and financial instruments. Traders reported being unable to close or adjust positions, leading to accusations of market manipulation and frustration over the reliance on a single point of failure. James Athey, a portfolio manager at Marlborough Investment Management Ltd., noted that trading conditions were noticeably thinner and wider due to the outage coinciding with month-end adjustments.
Official Statements & Responses
CME acknowledged the cooling issue, stating, “Our engineering teams, along with specialized mechanical contractors, are on-site working to restore full cooling capacity.” CyrusOne confirmed that its teams were working “around the clock” to address the malfunction. Despite these efforts, the outage raised questions about CME's contingency plans and the effectiveness of its disaster recovery strategies.
Criticism & Opposition
The incident sparked criticism from traders who expressed concerns over the vulnerability of CME's infrastructure. Timothy Bozman, a stock trader, questioned how a "simple issue" could lead to a complete halt of major markets, calling it a manipulation of sorts. The timing of the outage, occurring during a low-volume trading session post-Thanksgiving, further fueled speculation about its impact on market dynamics.
Conflicting Reports & Gaps
While CME's outage was officially attributed to a cooling failure, some traders speculated about the adequacy of the exchange's backup systems and whether the timing was coincidental. The lack of clear communication during the outage left many traders uncertain about when normal operations would resume, highlighting a gap in real-time updates.
What's Next?
As of late November 28, CME continued to work on restoring full trading capabilities, with FX trading on EBS having restarted but many futures and options contracts still in limbo. Analysts expect detailed post-mortems from CME and CyrusOne regarding the incident, alongside scrutiny from regulators about CME's business continuity plans, especially as it prepares to migrate significant workloads to Google Cloud in Chicago.
Verbatim Quotes
- “I woke up thinking my Wi-Fi was out,” — Ritik Katte, Chief Investment Officer, MCD Capital
- “Month-end, day after Thanksgiving, CME down. It’s not an ideal combo!” — James Athey, Portfolio Manager, Marlborough Investment Management Ltd.
- “How in the actual $@ could the entire Index Futures, FX Futures, Metals futures, Energy Futures, Agriculture Futures markets and options be halted because of a server overheating.” — Timothy Bozman, Stock Trader
This incident serves as a critical reminder of the systemic risks associated with centralized trading infrastructures and the importance of robust contingency planning in the financial markets.
