The 2010 Flash Crash – What It Was and the Causes Behind It

The 2010 Flash Crash: One of the Most Dramatic Market Events

One of the most notable flash crashes in financial history occurred on May 6, 2010, affecting equity futures and the broader stock market. During this event, the Dow Jones Industrial Average (DJIA) plunged more than 1,000 points within minutes, only to recover much of the loss shortly afterward. The entire episode lasted roughly 30 minutes, making it one of the fastest and most dramatic market swings ever recorded.

Timeline of the Flash Crash

In early May 2010, financial markets were already under pressure due to growing concerns over the Greek sovereign debt crisis. On the day of the crash, markets opened lower as investors reacted to rising economic uncertainty.

Around 2:30 p.m. (ET), liquidity in the futures market suddenly began to disappear. Buy-side liquidity in the E-mini S&P 500 futures market dropped from about $6.0 billion to $2.7 billion, while the VIX index, which measures market volatility, surged by 23%.

The most dramatic part of the crash occurred between 2:32 p.m. and 2:45 p.m.. During this period, a massive sell order of 75,000 E-mini S&P 500 futures contracts, worth approximately $4.1 billion, was executed in the market without being broken into smaller trades.

This large order triggered a rapid 5% decline in the E-mini S&P 500 futures price, prompting arbitrage traders to sell related assets in the stock market. As a result, the SPDR S&P 500 ETF (SPY) dropped by about 6%.

Liquidity continued to deteriorate as market makers and liquidity providers widened bid–ask spreads, reduced available liquidity, or temporarily withdrew from trading altogether.

This extreme market imbalance caused some stocks to trade at bizarre prices. Certain shares briefly dropped to $0.0001, while others spiked to $100,000. Meanwhile, the Dow Jones Industrial Average plunged roughly 1,000 points, marking the most visible impact of the crash.

At 2:45 p.m., trading in E-mini futures was halted on the Chicago Mercantile Exchange (CME), which helped stabilize the market and eventually allowed prices to recover.

Possible Causes of the Crash

Investigations later concluded that the flash crash was not caused by a single factor, but rather by a combination of events occurring simultaneously.

One major factor was the large futures sell order placed by the Waddell & Reed mutual fund, which was attempting to hedge a $75 billion investment portfolio.

Another contributing factor involved market manipulation by trader Navinder Sarao, who used a technique known as spoofing. Spoofing involves placing large orders with the intention of canceling them before execution in order to influence market prices. Under the Dodd–Frank Act, spoofing is considered illegal.

Regulators also noted that high-frequency trading (HFT) firms amplified the market decline. Although they did not trigger the crash, their rapid withdrawal from trading significantly reduced liquidity. Since high-frequency traders account for more than half of U.S. equity trading volume, their absence worsened the market instability.

Regulatory Changes After the Flash Crash

Following the event, regulators introduced several new safeguards designed to prevent similar market disruptions.

Two key measures include:

• Limit Up–Limit Down (LULD) mechanism
  This rule prevents trades from occurring outside predetermined price ranges. The allowed price bands are wider during market opening and closing periods.

• Market-Wide Circuit Breakers (MWCB)
  Introduced in 2012, these rules temporarily halt trading when markets experience severe declines. These circuit breakers were triggered several times during the COVID-19 market volatility in 2020.

Key Takeaway

Flash crashes have happened multiple times in financial markets and may occur again in the future. For investors, the most important response during such events is to remain calm and avoid panic selling. Although prices can fall dramatically during a flash crash, they often recover quickly once market conditions stabilize.