Program trading amounted to 17.6 million shares...

Program trading amounted to 17.6 million shares a day, or 12.1% of the New York Stock Exchange’s average daily volume of 145.7 million shares last month, the NYSE reported. August program trading--buying and selling stocks, stock futures and options by way of computerized strategies--was only 11.7 million shares a day, the exchange said. This amounted to 8.1% of the exchange’s average daily volume of 144.7 million shares. In all markets, program trading averaged 23.4 million shares a day in September, up from August’s 14.2 million shares.