A flash crash is a very rapid, deep, and volatile fall in security prices occurring within an extremely short time period.
Understanding flash crashes
Fellow Elephants, a flash crash happens when computer algorithms and high-frequency trading systems trigger massive, instantaneous sell orders. These crashes affect exchanges globally, from the London Stock Exchange to the Tokyo Stock Exchange. The primary driver is automated trading software reacting to specific market conditions or erroneous data inputs.
The defining characteristic of this event is the speed. Prices drop dramatically in a matter of minutes. As the initial sell orders hit the market, other algorithms detect the downward price movement and automatically begin selling their own holdings. This creates a feedback loop. During this time, market liquidity disappears. Buyers withdraw their bids, meaning there is no one left to purchase the securities being dumped.
The market typically recovers shortly after the drop. Once the algorithms reach their maximum loss limits or detect a price floor, the selling stops. Buyers re-enter the market to purchase discounted assets, driving prices back up to near their pre-crash levels. To mitigate these occurrences, international financial regulators and exchange operators now use circuit breakers. These are automatic mechanisms that pause trading – sometimes for a few minutes or the remainder of the day – when an index or individual stock falls by a predetermined percentage.
Example
Imagine a publicly traded agricultural firm called Savannah Peanuts PLC. Savannah Peanuts is a major supplier of feed for elephant sanctuaries across Africa and Asia. On a standard trading Tuesday, an erroneous news report is published stating a severe drought will destroy the entire peanut crop. A trading algorithm scans this headline and immediately sells 500,000 shares of Savannah Peanuts.
Other high-frequency trading programs see this massive sell order and interpret it as an incoming price collapse. They automatically dump their shares of Savannah Peanuts. The stock price plummets from $50 a share to $0.05 a share in three minutes. Human traders who manage elephant sanctuary endowment funds see the drop but cannot react fast enough.
Four minutes later, the news report is retracted as false. The algorithms recognize the error and begin buying the stock back at the extreme discount. Within ten minutes, the stock price of Savannah Peanuts returns to $49.50. The flash crash is over before most human investors even log into their brokerage accounts.