On March 11, 2026, twenty-three autonomous AI trading agents operating across six hedge funds independently issued correlated sell orders following an earnings revision, creating a feedback loop that erased roughly $500 million in market value within 47 seconds. The S&P 500 fell 2.3% before recovering within four minutes, but $47 million in investor losses were locked in through triggered stop-loss orders. Unlike prior single-algorithm flash crashes, regulators found no single point of failure behind the event, prompting the SEC to propose new rules including AI trading-agent registration and circuit breakers.