Credit Suisse failed to adhere to the principles of good business practice in that on Nov. 14, 2007, beginning at approximately 3:40 p.m., a Credit Suisse proprietary algorithm routed hundreds of thousands of cancel/replace requests to the New York Stock Exchange for orders that had been previously generated by the algorithm, but, due to an unforeseen programming issue, were never sent by the algorithm. The unusually large amount of cancel/replace messages contributed to the over-queuing of message traffic in all of the securities, approximately 975 in total, traded at five posts on the NYSE Trading Floor. Messages, including new orders, modifications of orders, and cancellation requests were frozen in queue and could not be immediately processed. These five posts could not be closed on time, ultimately closing between 4:10 p.m. and 4:27 p.m.
Credit Suisse violated NYSE Rule 342 by failing to properly supervise the development and implementation of the firm’s proprietary algorithm, particularly with respect to certain revisions to the algorithm that contributed to the Nov. 14 incident. The firm also failed to properly monitor the operation of the algorithm, as evidenced by the fact that the firm was unaware that hundreds of thousands of messages sent by the algorithm were being rejected by NYSE systems until being notified of the issue by NYSE Regulation the following day. These failures by the firm also constituted a bad business practice in violation of NYSE Rule 401.