Computer Problems Hinder Nasdaq Activity

The Nasdaq Stock Market said its computer systems failed during the final minutes of trading, leaving hundreds of stock brokers unable to see new price quotes.

Nasdaq, the second-largest stock market, also was unable to say immediately what caused its systems to malfunction, according to spokeswoman Judy Inosanto. Trading was halted, she said, though it was unclear for how long.

Computers that update stock quotes were apparently the first to fail. Then systems called SelectNet and SOES were shut down, she said. SelectNet circulates orders, and SOES provides automated trade execution.

Most Nasdaq activity occurs during the normal market hours from 9:30 a.m. to 4 p.m. EST, though some Nasdaq systems are used in trading that goes until 6:30 p.m. The effect on after-hours dealings was also unclear, Inosanto said.