The New York Stock Exchange released its weekly program-trading data submitted by its member firms. The report includes trading in all markets as reported to the NYSE for Apr. 16-20.

The data indicated that during Apr. 16-20, program trading amounted to 34.5 percent of NYSE average daily volume of 3,491.6 million shares, or 1,206.0 million program shares traded per day. This included program trading associated with the April 20 monthly expiration of stock-index options and futures.

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.

For the second quarter of 2007, the NYSE’s program-trading report includes profiles of program trading whenever the New York Stock Exchange Composite Index (NYA) moves 180 points or more in a single direction during any one-hour period. During Apr. 16-20, there were no such periods.

In all markets, program trading by member firms averaged 2,375.0 million shares a day during Apr. 16-20. About 50.8 percent of program trading took place on the NYSE, 3.5 percent in non-U.S. markets and 45.7 percent in other domestic markets, including Nasdaq, the American Stock Exchange and regional markets.