The data indicated that during June 23-27, program trading amounted to 34.5 percent of NYSE average daily volume of 4,973.0 million shares1, or 1,714.5 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 with a total value of $1 million or more.

In all markets, program trading by member firms averaged 4,542.8 million shares a day during June 23-27. About 37.7 percent of program trading took place on the NYSE, 0.4 percent in non-U.S. markets and 61.9 percent in other domestic markets, including Nasdaq, the American Stock Exchange and regional markets. -- www.nyse.com