May 10 (Bloomberg) -- Circuit breakers that halted trading on as many as 50 equity markets that compete with the New York Stock Exchange in the U.S. may have kept last weeks stock market plunge from snowballing, Dick Grasso said. Circuit breakers could have prevented a lot of what we saw last Thursday, Grasso, the former chief executive officer of the New York Stock Exchange, said in a Bloomberg Radio interview. The market fell 600 points and then recovered 600 points before anyone could finish their cup of coffee.
Almost 1.3 billion shares traded on U.S. markets in a 10- minute span starting at 2:40 p.m., six times the average, sending prices lower on platforms from New York to Kansas City. Nasdaq OMX Group Inc. said it canceled transactions in almost 300 stocks where swings grew too wide. Federal agencies began inquiries after the Dow Jones Industrial Average slumped almost 1,000 points intraday before paring losses.
While the first half of the plunge probably reflected normal trading as concern increased that Greeces credit crisis would spread, the selloff snowballed because of orders sent to venues with no investors willing to match them, NYSE chief operating officer Larry Leibowitz said in a Bloomberg Television interview last week.