some Republican members of the committee questioned the wisdom of regulators taking action before the causes of the market roller coaster were clear.
Although Schapiro gave greater weight to theories that a confluence of events were responsible, no regulator or exchange has provided a full account of events or concluded what caused a lightning-fast 700-point drop in the Dow Jones Industrial Average that rattled investors worldwide.
"The sudden evaporation of meaningful prices for many major exchange-listed stocks in the middle of a trading day is unacceptable and clearly contrary to the vital policy objective of maintaining fair and orderly financial markets," Schapiro said.
CFTC Chairman Gary Gensler said his agency asked some traders for "all communications" and positions related to E-mini Standard & Poor's 500 futures contracts. That suggested a more muscular thrust in the complicated probe
black leather platform pump clearance , and bolstered industry rumors circulating around that contract over the last five days.
Schapiro and Gensler both said that computer-driven high frequency trading (HFT) strategies may have exacerbated the sell-off when some of those firms stopped making markets in stocks and futures contracts.
But the regulators were unclear about how much of the 10-minute market plunge could be attributed to HFT firms temporarily turning off their machines.
Some lawmakers pounced on the rapid traders. California Democrat Brad Sherman questioned whether the fast traders should be subjected to a small tax.
The House has already passed a financial regulation reform bill in response to the recent financial crisis. The Senate is currently debating its own version.
Nasdaq OMX Group Inc said its internal analysis found no system malfunction or errant trade.
NYSE Euronext said the market's failure stemmed because the other trading venues did not follow the Big Board's circuit breakers.
Regulatory News
U.S. prosecutors stung accused Galleon hedge fund founder Raj Rajaratnam with one more phone tap recording as his lawyers rested the defense case on Monday at his trial on insider trading charges.
Rajaratnam
black leather platform pump clearance , the central figure in the biggest Wall Street insider trading trial in decades, sat expressionless in Manhattan federal court as the jury heard a September 30, 2008 FBI phone tap with co-conspirator and fellow trader Danielle Chiesi.
"Look, the other thing is right, it's been widely speculated. What people don't know is the time
black leather platform pump clearance ," Rajaratnam was heard telling Chiesi as they discussed chipmaker Advanced Micro Devices Inc's then imminent sale of a manufacturing business.
The recording was played during a brief prosecution rebuttal to the defense case, which rested on Monday. The jury will hear closing arguments from both sides starting on Wednesday.
Through dozens of phone taps and friends-turned-government witnesses
black leather platform pump clearance christian louboutin boutique Illustration, the government sought to prove that Rajaratnam timed his trades according to inside tips he received. The defense argued that much of the information