At 11:00 p.m. Central Time on November 27, 2025, the world’s most critical derivatives marketplace went dark—not from a cyberattack, not from a liquidity crisis, but from a broken air conditioner. The CME Group, operator of the CME Globex electronic trading platform, issued a terse alert: markets were halted due to a cooling issue at CyrusOne data centers. No one was named. No timeline given. Just silence, and the hum of servers overheating somewhere in Texas.
What Happened When the Cooling Failed
The first alert came at 23:00 CT. Four more followed—each identical, each a ghost of the last. At 23:32, 00:00, 00:31, and finally 01:00 CT on November 28, the Global Command Center in Chicago repeated the same message: support was working on it. "In the near term." That’s all. No details. No location. No backup systems activated. Just the same words, echoing into the void.This wasn’t a glitch. This was a cascade failure. CME Globex doesn’t run on its own servers. It relies on infrastructure leased from third-party data centers—specifically, those operated by CyrusOne, a Dallas-based colocation giant. The cooling system in one (or more) of those facilities failed. And when the temperature rose, the servers throttled. Then shut down. Then, the markets froze.
Think of it like this: imagine every stock trade, every oil futures contract, every euro-dollar swap happening on a single data center’s cooling system. One fan dies. Everything stops. No one’s trading. No one’s hedging. No one’s sleeping.
Who Was Affected—and How Deeply
The outage hit every product on CME Globex: Treasury futures, crude oil, soybeans, Bitcoin futures, S&P 500 options, even the tiny agricultural contracts that farmers in Iowa use to lock in prices. All gone. For over two hours during the overnight session, when Asian and European traders rely on U.S. markets to price their own positions, there was nothing. No bids. No offers. Just a digital black hole.Wall Street firms, hedge funds, prop trading shops—all were blindsided. One Chicago-based quant trader, who spoke anonymously, said, "We had a position open on 10-year Treasury futures. We couldn’t exit. Couldn’t adjust. We just watched the numbers tick up on our screens, knowing we were stuck while the market moved without us. It’s terrifying when the system you trust just… turns off."
And here’s the kicker: this wasn’t the first time a data center cooling failure caused trouble. In 2021, a similar outage at a Microsoft Azure facility in Virginia knocked out parts of the Nasdaq trading system. In 2023, a cooling malfunction at a London-based data center halted FX trading for 47 minutes. But those were partial outages. This was total. Complete. And it happened during one of the busiest trading windows of the day.
The Hidden Infrastructure Behind Your Trades
Most people think trading happens on the floor of the Chicago Mercantile Exchange. It doesn’t. Not anymore. Over 99% of CME’s volume flows through CME Globex, which runs on a network of third-party data centers. CyrusOne is one of the biggest. It operates 30+ facilities across the U.S. and Europe. But the exact location of the failed unit? Still undisclosed. That’s a problem.Why? Because if you’re a global institutional investor, you need to know where your risk is concentrated. If one cooling system can shut down the entire U.S. derivatives market, then the infrastructure is too centralized. Too fragile. Too dependent on a single vendor’s environmental controls.
And yet, CME Group has never publicly disclosed which CyrusOne facilities host its core systems. No map. No redundancy plan shared. Just a press release that says, "We’re working on it."
What Comes Next? The Real Risk Is Still Out There
The CME Group says it will notify clients about Pre-Open procedures once the issue is resolved. But what does "resolved" mean? Did they fix the cooling? Did they switch to a backup facility? Did they reroute traffic? No one says.Regulators haven’t commented. The CFTC, which oversees derivatives markets, issued no statement. The SEC, which watches equity-linked products, stayed silent. That’s not normal. When a market halts for more than 90 minutes, especially during active hours, regulators usually step in. They don’t this time. Why?
Maybe because they know this isn’t an isolated incident. It’s a symptom. As financial markets become more digital, more reliant on third-party infrastructure, and more dependent on real-time data flows, the attack surface expands—not just from hackers, but from HVAC technicians.
And here’s the truth: if a cooling system can shut down the world’s largest derivatives exchange, then no market is truly safe. Not even the ones you think are bulletproof.
Why This Matters to You
You might not trade futures. But if you have a 401(k), a pension, or even a mutual fund, you’re exposed. Those funds invest in Treasury futures, equity index options, and commodity contracts. When those markets freeze, prices become distorted. Volatility spikes. Liquidity vanishes. And when markets reopen, they don’t always snap back cleanly.This outage didn’t just stop trading. It eroded trust. And trust, once broken in financial markets, takes years to rebuild.
Frequently Asked Questions
How long did the CME Globex market halt last, and when did it end?
The market halt began at 23:00 CT on November 27, 2025, and persisted through at least 01:00 CT on November 28, 2025—a minimum of 2 hours and 1 minute. No official resumption notice was issued in the final alert, leaving traders uncertain whether trading had resumed or if the system was still offline. CME Group has not confirmed the exact time markets reopened.
Which specific products were affected by the outage?
All futures and options traded on CME Globex were suspended, including U.S. Treasury futures, S&P 500 and Nasdaq-100 index options, crude oil and natural gas contracts, foreign exchange pairs like EUR/USD, and agricultural products such as corn and soybeans. Even Bitcoin futures, introduced in 2017, were halted—showing how deeply digital assets are now tied to traditional financial infrastructure.
Why didn’t CME Group switch to backup systems?
CME Group has never disclosed its full redundancy architecture. Industry insiders suggest that while some systems have failover protocols, the core trading engine may be physically tied to the CyrusOne facilities where the cooling failure occurred. Without a geographically separate, fully independent data center hosting the primary matching engine, switching over isn’t as simple as flipping a switch.
Has CyrusOne had similar outages before?
Public records show no prior cooling-related outages directly impacting CME Globex. However, CyrusOne has experienced other incidents: a power surge in its Atlanta facility in 2022 disrupted cloud services for several fintech clients, and a network partition in 2023 briefly affected enterprise customers. But none matched the scale of this financial market disruption, which underscores the unique vulnerability of trading infrastructure.
What’s the financial impact of this outage?
CME Group has not released any figures on lost trading volume or client losses. However, during a typical overnight session, CME Globex processes over $1.2 trillion in notional value. Even a two-hour halt likely caused hundreds of millions in missed trades, slippage, and hedging failures—costs absorbed by hedge funds, banks, and asset managers, not the exchange itself.
Could this happen again—and how can traders prepare?
Yes. With reliance on third-party data centers and no public disclosure of redundancy plans, the risk remains high. Traders should diversify execution venues where possible, use multi-data center brokers, and demand transparency from their clearinghouses. Regulatory pressure is growing for exchanges to disclose infrastructure dependencies—something CME Group has so far resisted.