Record-Breaking Activity

The New York Stock Exchange measures market activity by the number of investor messages it processes in any given day, as opposed to the number of shares traded. On July 26, the NYSE processed 695 million messages, a 27% jump from its previous record of 548 million messages processed a day earlier. The NYSE Group, which includes the Archipelago Exchange it acquired last year, traded 5.1 billion shares on July 26, its second-most-active day after setting an all-time record of 5.19 billion shares on June 22.

The NASDAQ Stock Market reported 1.7 billion messages processed on July 26, up 42% from the prior record on Feb. 27, and it entered a record 326 million orders, a 59% jump from the previous high in February.

Cleveland Rueckert, a research analyst at Birinyi Associates in New York, believes volatility was the key contributor to the record trading volumes on July 26. "With the whole subprime thing, and the financial sector sort of falling apart, you have people who are getting nervous," he says.

Corporate earnings are affecting trading decisions, as is the approach of the end of the month, when mutual funds disclose performance information to investors. That's likely spurring portfolio managers to lock in profits by selling stocks they think have topped out, Rueckert says.