On October 2, 2002, a clerk at Bear Stearns had erroneously entered an order to sell nearly $4 billion worth of securities.  The trader had sent the clerk an order to sell $4 million worth.  Only $622 million of the orders were executed when the error was found and the remainder of the orders were cancelled.  Reports stated that it was a human error, not a computer error, and that it was the fault of the clerk, not the trader.    What is your opinion of these reports?  What controls could have prevented this error?