In 2012, Knight Capital, a major player in US equities trading due to its high-frequency trading algorithms, faced a catastrophic failure due to the misuse of a feature gate originally created for a test algorithm called "Power Peg." This algorithm, intended only for testing, was mistakenly deployed in a live trading environment due to an error in their Smart Market Access Routing system, leading to the execution of unintended trades and a consequential $440 million loss. This loss rendered Knight Capital insolvent, as it exceeded their $360 million in assets, necessitating a rescue by external investors. The incident highlights the importance of carefully managing legacy code and creating distinct feature gates to prevent such costly errors. The text also briefly touches on broader themes of experimentation culture, infrastructure, and learning from failures, with references to industry insights and changes in market strategies influenced by data-driven approaches like A/B testing.