May 6, 2010 United States stock market flash crash

May 6, 2010 United States stock market flash crash
Name	May 6, 2010 United States stock market flash crash
Date	May 6, 2010
Location	New York City, Chicago, United States
Type	Stock market crash
Markets	New York Stock Exchange, NASDAQ, Chicago Mercantile Exchange
Casualties	None

May 6, 2010 United States stock market flash crash was a sudden, severe plunge and rapid recovery in price levels across multiple United States equity and futures markets on 6 May 2010. The episode affected major venues including the New York Stock Exchange, NASDAQ Stock Market, and Chicago Mercantile Exchange, provoking investigations by the Securities and Exchange Commission and the Commodity Futures Trading Commission. It prompted debate among participants such as Goldman Sachs, JPMorgan Chase, Citigroup, and BlackRock about automated trading, market structure, and regulatory safeguards.

Background

In the months before May 2010, market participants from Morgan Stanley to Bank of America had expanded use of algorithmic trading and high-frequency trading firms including GETCO and Virtu Financial had grown. Equity venues such as the NYSE Arca, BATS Global Markets, and Direct Edge competed with legacy exchanges, while derivatives activity at the Chicago Board Options Exchange and CME Group increased. Macroeconomic events such as concerns about sovereign debt in Greece, actions by the European Central Bank, and statements from the International Monetary Fund contributed to market volatility. Regulators including the Federal Reserve System, Office of the Comptroller of the Currency, and the Department of the Treasury monitored stability risks, and new technology from firms like ITG and Knight Capital Group had altered order routing practices.

Timeline of events

On the morning of 6 May 2010, equity indices including the Dow Jones Industrial Average, S&P 500, and NASDAQ Composite traded under pressure after news flows involving Standard & Poor's credit commentary and developments related to Spain and Portugal. At approximately 2:32 p.m. Eastern Time, liquidity conditions deteriorated as rapid selling propagated through markets connected by venues such as NYSE MKT and NYSE Arca Options. Within minutes, several blue-chip stocks listed at New York Stock Exchange experienced steep intraday declines, with quotes and trade prints showing dislocations on order books of firms like Citadel LLC, Two Sigma Investments, and Renaissance Technologies. The CME Group futures markets, including the E-mini S&P 500 futures, exhibited sharp moves that fed back into cash equity trading through programs operated by Barclays, Deutsche Bank, Credit Suisse, and UBS. By about 3:07 p.m., many prices had recovered as liquidity providers returned and exchanges applied protocols such as trading pauses used by NASDAQ Stock Market and the NYSE Regulation. Exchanges and market participants including Interactive Brokers and Fidelity Investments later reported anomalous executions and communications problems.

Causes and contributing factors

Analyses by the Securities and Exchange Commission and the Commodity Futures Trading Commission identified a combination of factors: an aggressive sell order executed by a mutual fund complex using an automated execution algorithm operated by Waddell & Reed-related accounts; interaction with aggressive liquidity-taking by entities such as Highbridge Capital Management; and fragile order books across competing venues including BATS Global Markets and Direct Edge. Structural issues pointed to fragmentation among venues like NYSE Arca, NYSE MKT, and NASDAQ OMX Group; order types and routing practices used by broker-dealers such as Knight Capital Group; and the role of proprietary firms including Virtu Financial and GETCO in providing or withdrawing liquidity. Market mechanisms such as the Limit Up-Limit Down system were not fully implemented at the time, and coordinated circuit breakers for individual securities were absent, exacerbating rapid price moves noted by academics from Massachusetts Institute of Technology, Columbia University, and Stanford University.

Market impact and losses

During the episode, liquidity evaporated in many stocks, producing erroneous prints and trades for firms listed at NYSE and NASDAQ. Individual securities such as Procter & Gamble, Accenture, and Apple Inc. showed extreme intraday bid-ask spreads and temporary price collapses that affected institutional investors including Vanguard Group, T. Rowe Price, and BlackRock. Market-wide indices such as the Dow Jones Industrial Average experienced swings of about 1,000 points within minutes, creating notional losses across equity portfolios managed by State Street Corporation, Northern Trust, and Walmart pension funds. Proprietary traders and market makers, including Citadel LLC and Two Sigma Investments, reported rapid resets in risk models; some counterparties sought emergency liquidity from banks like JPMorgan Chase and Bank of America. While direct cash-settled losses were substantial for some participants, broader financial system contagion was limited, and major firms including Goldman Sachs avoided systemic failure.

Regulatory and policy responses

Following the event, the SEC and CFTC formed a joint committee and later released the "Joint Report" analyzing technological and market structure causes, prompting regulatory measures. The SEC accelerated adoption of the Limit Up-Limit Down mechanism and mandated single-stock circuit breakers coordinated across venues including NYSE Arca and NASDAQ OMX Group. Changes affected order handling rules under Regulation National Market System and disclosure requirements for broker-dealers such as Knight Capital Group and Citadel LLC. Legislative attention from members of United States Congress and committees including the House Financial Services Committee and the Senate Committee on Banking, Housing, and Urban Affairs produced hearings featuring testimony from executives of BATS Global Markets, NYSE Euronext, NYSE Regulation, and academic witnesses from Harvard University and University of Chicago.

Legal actions and investigations

After the flash event, investigations by the SEC and CFTC focused on algorithms, order flow, and the trade executed by a mutual fund adviser affiliated with Waddell & Reed Financial; the SEC charged an entity in subsequent enforcement actions relating to market manipulation and recordkeeping. Civil litigation followed, with class-action suits filed by institutional investors naming brokers and exchanges including NYSE Arca and BATS Global Markets as defendants. Internal reviews at firms such as Knight Capital Group and regulatory settlements with Citadel LLC-affiliated entities resolved some disputes. Parallel probes by the Department of Justice and state attorneys general examined whether criminal conduct occurred, and academic and industry reports from Financial Industry Regulatory Authority and PIMCO informed ongoing reforms.

Category:2010 in finance Category:Stock market crashes Category:Financial markets in the United States