The New York Stock Exchange reported that for the week ending September 13, program trading accounted for 24.5 percent of its total volume.
A subsidiary of NYSE Euronext released its weekly program-trading data compiled from member firms’ executed volume from NYSE’s orders database. The data indicated that during September 9 through 13, program trading amounted to almost 25 percent of the NYSE’s average daily volume of 1,386.0 million shares1, or 339.5 million program shares traded per day.
Program trading encompasses a wide range of portfolio-trading strategies involving the purchase or sale of a basket of at least 15 stocks.

