From the (http://www.reuters.com/article/idUSTRE6341EA20100506),
The Dow suffered its biggest ever intraday point drop, which may have been caused by an erroneous trade entered by a person at a big Wall Street bank, multiple market sources said.
and the suspected cause? A UI Glitch!
In one of the most dizzying half-hours in stock market history, the Dow plunged nearly 1,000 points before paring those losses—all apparently due to a trader error.
According to multiple sources, a trader entered a “b” for billion instead of an “m” for million in a trade possibly involving Procter & Gamble , a component in the Dow. (CNBC’s Jim Cramer noted suspicious price movement in P&G stock on air during the height of the market selloff. Watch.)
Sources tell CNBC the erroneous trade may have been made at Citigroup .
“We, along with the rest of the financial industry, are investigating to find the source of today’s market volatility,” Citigroup said in a statement. “At this point we have no evidence that Citi was involved in any erroneous transaction.”
According to a person familiar with the probe, one focus is on futures contracts tied to the Standard & Poor’s 500 stock index, known as E-mini S&P 500 futures, and in particular a two-minute window in which 16 billion of the futures were sold.
Citigroup’s total E-mini volume for the entire day was only 9 billion, suggesting that the origin of the trades was elsewhere, according to someone close to Citigroup’s own probe of the situation. The E-minis trade on the CME.
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