The order about 20 minutes before the closing bell was the result of a "clerical error" and should have been entered as $4 million, the exchange said in a statement. All but $622 million of the orders were cancelled before execution, it said.
Bear Stearns told Reuters the error will have no material impact on the company and declined to comment further.
"When a large brokerage house like Bear Stearns sells a large quantity of anything, people assume Bear Stearns knows something and it will move the price," said Daniel Weaver, associate professor of finance at the Zicklin School of Business at New York's Baruch College. "It was a bear sign from Bear Stearns."
"It's not very common," said Richard Repetto, an analyst with Putnam Lovell NBF, of seeing this type of error on the New York Stock Exchange. "This is a human error; it's not an electronic error."
Weaver said he expects Bear Stearns to try to unwind, or cancel, the trades that were executed.
"But you have to have the other person willing to do it," he said. "It depends on their relationship with the other brokers. Since it happens to everybody, some of them are going to be willing to do it to the extent that they can."