One of the largest losses in history from unauthorized securities trading involved a securities trader for a French bank. The trader was able to circumvent internal controls and create over a billion in trading losses. The trader apparently escaped detection by using knowledge of the bank's internal control systems learned from a previous back office monitoring job. Much of this monitoring involved the use of software to monitor trades. The traders were usually kept to tight spending limits. However, these controls failed in this case.

What general weaknesses in internal controls contributed to the occurrence and size of the losses?