The Nasdaq stock market experienced a 34-minute trading halt on August 2, 1994, after a squirrel chewed through a power line connected to its primary data center in Connecticut.

Key Points

• A squirrel caused a power failure at the Nasdaq’s Trumbull, Connecticut, facility, triggering a nationwide trading freeze for 34 minutes.
• The exchange’s automated backup system failed to activate, leaving thousands of brokers unable to process orders for over 4,000 stock issues.
• A similar squirrel-related outage occurred at the same location in 1987, which lasted 82 minutes and caused significant damage to the facility's mainframes.
• The 1994 incident prompted investigations by Congress and the SEC, forcing Nasdaq to adopt a more robust, geographically distributed architecture.
• Squirrels remain a leading cause of power grid interruptions in the United States due to their tendency to gnaw on electrical equipment.

Why it Matters

The 1994 outage serves as a critical case study in engineering, highlighting the dangers of "single points of failure" in essential financial infrastructure. It forced the industry to move away from centralized data hubs toward the redundant, multi-site systems that now underpin modern global markets.