Flash crash
In modern finance, a flash crash is a very rapid, deep, and volatile fall in security prices occurring within a very short time period followed by a quick recovery. Flash crashes are frequently blamed by media on trades executed by black-box trading, combined with high-frequency trading, whose speed and interconnectedness can result in the loss and recovery of billions of dollars in a matter of minutes and seconds, but in reality occur because almost all participants have pulled their liquidity and temporarily paused their trading in the face of a sudden increase in risk.