Net Net: Promoting innovation and managing change
Net Net: Promoting innovation and managing change

How One Trade Set Off Flash Crash

Today’s joint Securities and Exchange Commission and the Commodity Futures Trading Commission report discussed the causes of the May 6 Flash Crash in detail.

NYSE Trader
Photo: Oliver Quillia for CNBC.com

The most surprising revelation in the report is that a single trade, against a backdrop of high volatility and downward price pressure, seems to have been responsible for the crash.

A firm identified by officials as Waddell & Reed Financial of Kansas attempted to execute an algorithmic sale of 75,000 S&P 500 futures contracts, referred to as E-minis, valued at $4.5 billion, in order to hedge an existing equity position.  

The algorithm was programmed to sell the E-minis so that the sell volume was to equal 9 percent of the total volume, calculated over the previous minute; however, the algorithm did not specify the sell price or the time frame of the trade.