The flash crash of May 6, 2010, also known as the crash of 2:45 or simply the flash crash, was a United States trillion-dollar flash crash (a type of stock market crash) which started at 2:32 p.m. EDT and lasted for approximately 36 minutes.
A variety of explanations have been forwarded for the crash, including errors in automatic trading systems and deliberate market manipulation.
Overview
Stock indices, such as the S&P 500, Dow Jones Industrial Average and Nasdaq Composite, collapsed and rebounded very rapidly. The Dow Jones Industrial Average had its second biggest intraday point decline (from the opening) up to that point, plunging 998.5 points (about 9%), most within minutes, only to recover a large part of the loss. It was also the second-largest intraday point swing (difference between intraday high and intraday low) up to that point, at 1,010.14 points. The prices of stocks, stock index futures, options and exchange-traded funds (ETFs) were volatile, thus trading volume spiked. A CFTC 2014 report described it as one of the most turbulent periods in the history of financial markets.
New regulations put in place following the 2010 flash crash proved to be inadequate to protect investors in the August 24, 2015 flash crash—"when the price of many ETFs appeared to come unhinged from their underlying value"—and ETFs were subsequently put under greater scrutiny by regulators and investors.
On April 21, 2015, nearly five years after the incident, the U.S. Department of Justice laid 22 criminal counts, including fraud and market manipulation, against Navinder Singh Sarao, a British financial trader. Among the charges included was the use of spoofing algorithms; just prior to the flash crash, he placed orders for thousands of E-mini S&P 500 stock index futures contracts which he planned on canceling later. These orders amounting to about "$200 million worth of bets that the market would fall" were "replaced or modified 19,000 times" before they were canceled. Spoofing, layering, and front running are now banned.
The Commodity Futures Trading Commission (CFTC) investigation concluded that Sarao "was at least significantly responsible for the order imbalances" in the derivatives market which affected stock markets and exacerbated the flash crash. Sarao began his alleged market manipulation in 2009 with commercially available trading software whose code he modified "so he could rapidly place and cancel orders automatically". Traders Magazine journalist, John Bates, argued that blaming a 36-year-old small-time trader who worked from his parents' modest stucco house in suburban west London for sparking a trillion-dollar stock market crash is "a little bit like blaming lightning for starting a fire" and that the investigation was lengthened because regulators used "bicycles to try and catch Ferraris". Furthermore, he concluded that by April 2015, traders can still manipulate and impact markets in spite of regulators and banks' new, improved monitoring of automated trade systems.
In May 2014, a CFTC report concluded that high-frequency traders "did not cause the Flash Crash, but contributed to it by demanding immediacy ahead of other market participants".
Some recent peer-reviewed research shows that flash crashes are not isolated occurrences, but have occurred quite often. Gao and Mizrach studied US equities over the period of 1993–2011. They show that breakdowns in market quality (such as flash crashes) have occurred in every year they examined and that, apart from the financial crisis, such problems have declined since the introduction of Reg NMS. They also show that 2010, while infamous for the flash crash, was not a year with an inordinate number of breakdowns in market quality.
Background
On May 6, 2010, U.S. stock markets opened and the Dow was down, and trended that way for most of the day on worries about the debt crisis in Greece. At 2:42 p.m., with the Dow down more than 300 points for the day, the equity market began to fall rapidly, dropping an additional 600 points in 5 minutes for a loss of nearly 1,000 points for the day by 2:47 p.m. Twenty minutes later, by 3:07 p.m., the market had regained most of the 600-point drop. At the time of the flash crash, in May 2010, high-frequency traders were taking advantage of unintended consequences of the consolidation of the U.S. financial regulations into Regulation NMS, designed to modernize and strengthen the United States National Market System for equity securities. The Reg NMS, promulgated and described by the United States Securities and Exchange Commission, was intended to assure that investors received the best price executions for their orders by encouraging competition in the marketplace, but created attractive new opportunities for high-frequency-traders. Activities such as spoofing, layering and front running were banned by 2015. This rule was designed to give investors the best possible price when dealing in stocks, even if that price was not on the exchange that received the order.
Explanation
Early theories
At first, while the regulatory agencies and the United States Congress announced investigations into the crash, no specific reason for the 600-point plunge was identified. Investigators focused on a number of possible causes, including a confluence of computer-automated trades, or possibly an error by human traders. By the first weekend, regulators had discounted the possibility of trader error and focused on automated trades conducted on exchanges other than the NYSE. However, CME Group, a large futures exchange, stated that, insofar as stock index futures traded on CME Group were concerned, its investigation found no evidence for this, or that high-frequency trading played a role, and in fact concluded that automated trading had contributed to market stability during the period of the crash. Others speculate that an intermarket sweep order may have played a role in triggering the crash.
Several plausible theories were put forward to explain the plunge.
- The fat-finger theory: In 2010 immediately after the plunge, several reports indicated that the event may have been triggered by a fat-finger trade, an inadvertent large "sell order" for Procter & Gamble stock, inciting massive algorithmic trading orders to dump the stock; however, this theory was quickly disproved after it was determined that Procter and Gamble's decline occurred after a significant decline in the E-Mini S&P 500 futures contracts. The "fat-finger trade" hypothesis was also disproved when it was determined that existing CME Group and ICE safeguards would have prevented such an error.
- Impact of high frequency traders: Regulators found that high frequency traders exacerbated price declines. Regulators determined that high frequency traders sold aggressively to eliminate their positions and withdrew from the markets in the face of uncertainty. A July 2011 report by the International Organization of Securities Commissions (IOSCO), an international body of securities regulators, concluded that while "algorithms and HFT technology have been used by market participants to manage their trading and risk, their usage was also clearly a contributing factor". Other theories postulate that the actions of high frequency traders (HFTs) were the underlying cause of the flash crash. One hypothesis, based on the analysis of bid–ask data by Nanex, LLC, is that HFTs send non-executable orders (orders that are outside the bid–ask spread) to exchanges in batches. Though the purpose of these orders is not publicly known, some experts speculate that their purpose is to increase noise, clog exchanges, and outwit competitors. However, other experts believe that deliberate market manipulation is unlikely because there is no practical way in which the HFTs can profit from these orders, and it is more likely that these orders are designed to test latency times and to detect early price trends. Whatever the reasons behind the existence of these orders, this theory postulates that they exacerbated the crash by overloading the exchanges on May 6. On September 3, 2010, the regulators probing the crash concluded: "that quote-stuffing—placing and then almost immediately cancelling large numbers of rapid-fire orders to buy or sell stocks—was not a 'major factor' in the turmoil". Some have put forth the theory that high-frequency trading was actually a major factor in minimizing and reversing the flash crash.
- Large directional bets: Regulators said a large E-Mini S&P 500 seller set off a chain of events triggering the Flash Crash, but did not identify the firm. Earlier, some investigators suggested that a large purchase of put options on the S&P 500 index by the hedge fund Universa Investments shortly before the crash may have been among the primary causes. Other reports have speculated that the event may have been triggered by a single sale of 75,000 E-Mini S&P 500 contracts valued at around $4 billion by the Overland Park, Kansas, firm Waddell & Reed on the Chicago Mercantile Exchange. Others suspect a movement in the U.S. Dollar to Japanese yen exchange rate.
- Changes in market structure: Some market structure experts speculate that, whatever the underlying causes, equity markets are vulnerable to these sorts of events because of decentralization of trading.
- Technical glitches: An analysis of trading on the exchanges during the moments immediately prior to the flash crash reveals technical glitches in the reporting of prices on the NYSE and various alternative trading systems (ATSs) that might have contributed to the drying up of liquidity. According to this theory, technical problems at the NYSE led to delays as long as five minutes in NYSE quotes being reported on the Consolidated Quotation System (CQS) with time stamps indicating that the quotes were current. However, some market participants (those with access to NYSE's own quote reporting system, OpenBook) could see both correct current NYSE quotes, as well as the delayed but apparently current CQS quotes. At the same time, there were errors in the prices of some stocks (Apple Inc., Sothebys, and some ETFs). Confused and uncertain about prices, many market participants attempted to drop out of the market by posting stub quotes (very low bids and very high offers) and, at the same time, many high-frequency trading algorithms attempted to exit the market with market orders (which were executed at the stub quotes) leading to a domino effect that resulted in the flash crash plunge.
SEC/CFTC report
On September 30, 2010, after almost five months of investigations led by Gregg E. Berman, the U.S. Securities and Exchange Commission (SEC) and the Commodity Futures Trading Commission (CFTC) issued a joint report titled "Findings Regarding the Market Events of May 6, 2010" identifying the sequence of events leading to the flash crash.
The joint 2010 report "portrayed a market so fragmented and fragile that a single large trade could send stocks into a sudden spiral", and detailed how a large mutual fund firm selling an unusually large number of E-Mini S&P contracts first exhausted available buyers, and then how high-frequency traders (HFT) started aggressively selling, accelerating the effect of the mutual fund's selling and contributing to the sharp price declines that day.
The SEC and CFTC joint 2010 report itself says that "May 6 started as an unusually turbulent day for the markets" and that by the early afternoon "broadly negative market sentiment was already affecting an increase in the price volatility of some individual securities". At 2:32 p.m. (EDT), against a "backdrop of unusually high volatility and thinning liquidity" that day, a large fundamental trader (known to be Waddell & Reed Financial Inc.) "initiated a sell program to sell a total of 75,000 E-Mini S&P contracts (valued at approximately $4.1 billion) as a hedge to an existing equity position". The report says that this was an unusually large position and that the computer algorithm the trader used to trade the position was set to "target an execution rate set to 9% of the trading volume calculated over the previous minute, but without regard to price or time".