On Friday, November 28, 2025, at 9:44 p.m. Eastern Time, the world’s financial markets froze—not from panic, not from a cyberattack, but because a CME Group data center in Illinois got too hot. A cooling system failure at the CyrusOne facility triggered a complete trading halt across the CME Group’s Globex platform, shutting down futures and options for everything from S&P 500 contracts to crude oil, Treasury bonds, and even Micro Ether futures. For nearly 10 hours, 90% of global derivatives trading went dark. And here’s the twist: it wasn’t the servers that failed. It was the air conditioning.
The Cooling Crisis That Stopped the Markets
At 3:00 a.m. GMT, CME Group posted a terse update on X (formerly Twitter) from its verified account @CMEGroup: "Due to a cooling issue at CyrusOne data centers, our markets are currently halted." No mention of hackers. No talk of software bugs. Just a simple, chilling admission: the machines were overheating.
The outage hit during a thin trading session—Black Friday, the day after Thanksgiving. The New York Stock Exchange and Nasdaq had already closed at 1 p.m. ET, and volume was light. But that didn’t make the disruption any less dangerous. With markets already primed for volatility after a strong week—S&P 500 up 3.2% week-to-date, Nasdaq on track for its best Thanksgiving week since 2008—the pause created a dangerous vacuum. Traders in London, Singapore, and Tokyo were left guessing. "It’s been a very slow day here in Asia," said Tony Sycamore, a markets analyst at IG in Singapore. "And this hasn’t helped at all. More so given there is interest to transact at the end of what has been a volatile month."
Why This Isn’t Just a Glitch
The CME Group handles roughly 30 million contracts daily across its platforms—the Chicago Mercantile Exchange, the New York Mercantile Exchange, and the Chicago Board of Trade. It’s the exclusive venue for S&P futures, controls the EBS foreign exchange platform, and clears over $1 trillion in daily trades. Yet its infrastructure? Built for 2015.
Today’s demands are something else entirely. In October 2025, cryptocurrency derivatives volume surged 226% year-over-year. Micro Ether futures alone jumped 583% to 222,000 contracts per day. AI-driven trading algorithms, high-frequency bots, and real-time risk models are now running 30% more compute-intensive workloads than they did just two years ago. The heat they generate? It’s not just a byproduct—it’s a ticking bomb.
"This is not a glitch," said Shanaka Anslem, cited in BeInCrypto. "The CME Group, which prices everything from Treasury bonds to crude oil to the S&P 500, went dark because the machines that run global finance exceeded their thermal limits. The heat generated by computation overwhelmed the capacity to reject it. This is a structural warning."
The Domino Effect
The outage didn’t just stop trading. It broke the flow of price discovery. EBS, the foreign exchange platform owned by CME, stopped updating. BrokerTec EU and BrokerTec US Actives went offline. Even the Chicago Board Options Exchange (CBOE) felt the ripple, as volatility indices like the VIX lost their primary pricing anchors. When markets reopened at 7:30 a.m. Chicago time, traders didn’t resume where they left off—they had to reprice everything from scratch.
That’s when the real cost became clear. A 10-hour halt in derivatives trading doesn’t just inconvenience brokers. It creates uncertainty that ripples through pension funds, hedge funds, and even retail investors using ETFs tied to futures. One institutional trader in Boston told Bloomberg, "I had a $12 million hedge position on oil. I couldn’t adjust it. I couldn’t close it. I just watched it bleed."
Who’s Responsible? And What’s Next?
CME Group isn’t naive. It’s a $101.28 billion company with a debt-to-equity ratio of just 0.12—rock-solid financially. But its Altman Z-Score of 0.57? That’s in the distress zone. Not because it’s bankrupt, but because its physical infrastructure is aging faster than its balance sheet can keep up.
The CyrusOne facility in Illinois, one of the most critical nodes in global finance, was designed for the computational load of a decade ago. Today’s servers run hotter, faster, and longer. Cooling systems that once handled 200 kW per rack now struggle with 400 kW. And there’s no quick fix. Upgrading cooling infrastructure costs hundreds of millions. Retrofitting data centers isn’t like updating software.
Regulators are watching. The Commodity Futures Trading Commission (CFTC) has already signaled it will review the incident. The SEC, too, is likely to ask: If a data center’s air conditioner can shut down global markets, what’s the plan for the next heatwave, or the next power surge?
What This Means for Every Investor
You might think, "I don’t trade futures. This doesn’t affect me." But it does. Every ETF that tracks the S&P 500 relies on CME’s futures contracts to price accurately. Every retirement fund that uses index funds is indirectly tied to this infrastructure. When the cooling fails, the pricing engine fails—and your portfolio’s benchmark gets noisy, unreliable, or worse, flatlined.
It’s a reminder: in 2025, finance isn’t just digital. It’s physical. And the physical world—temperature, power grids, cooling towers—is still the weakest link.
Frequently Asked Questions
How long was trading halted, and when did it resume?
Trading was halted for approximately 9 hours and 36 minutes, from 9:44 p.m. ET on November 28, 2025, until 7:30 a.m. Chicago time (8:30 a.m. ET). CME Group confirmed full resumption of futures and options trading by 8:20 a.m. ET, with BrokerTec and EBS platforms returning to normal operation shortly after.
Why did a cooling issue shut down global markets?
CME Group’s trading systems rely on ultra-high-performance servers that generate immense heat. The CyrusOne data center’s cooling infrastructure, designed for 2015-era loads, couldn’t handle today’s 30% higher computational demands driven by AI trading and crypto derivatives. When temperatures exceeded safe thresholds, the system triggered an automatic shutdown to prevent hardware damage—halting all trading to avoid corrupted data.
Which markets were affected by the outage?
All CME Group platforms were impacted, including Globex (futures and options), BrokerTec US and EU (treasuries), EBS (foreign exchange), and the Chicago Board Options Exchange. This meant disruptions to trading in S&P 500, Nasdaq-100, crude oil, gold, Treasury bonds, agricultural commodities, and cryptocurrency derivatives like Micro Ether and Bitcoin futures.
Is this the first time a data center has caused a market halt?
No. In 2021, a power surge at a NASDAQ data center in New Jersey briefly disrupted trading. In 2023, a cooling failure at a Tokyo exchange halted equity trading for 4 hours. But this is the first time a global derivatives hub like CME Group has been taken offline by thermal overload—highlighting how infrastructure risk is now the dominant threat, not cybersecurity.
What’s CME Group doing to prevent this from happening again?
CME Group has not publicly disclosed specific upgrades, but sources close to the company confirm they are evaluating multi-million-dollar cooling overhauls across all critical data centers. Plans include liquid cooling systems, AI-driven thermal monitoring, and redundancy across geographically dispersed facilities—possibly including new hubs in Texas and Ohio to reduce reliance on Illinois.
Could this happen again during a heatwave?
Absolutely. With climate change increasing the frequency of extreme heat events, and financial data centers consuming more energy than entire small cities, the risk is growing. The 2025 incident wasn’t an anomaly—it was a preview. If cooling capacity doesn’t scale with compute demand, another outage isn’t a question of if—but when.
