Computer Glitch Delays Start of Big Board Trading

The start of trading on the New York Stock Exchange was postponed for an hour Monday because of a computer system problem, the first such delay in nearly five years.

The problem was traced to malfunctioning software that caused trouble in a computer that links the world’s biggest exchange’s data-processing system with electronic displays on the floor of the Big Board, NYSE officials said.

The officials said a malfunction in the software was first detected about 4:30 a.m. EST. The glitch caused a computer to send an abnormally large number of messages to the exchange floor. The computer links the main data-processing operation with electronic books at the exchange.

As a result, small-investor and other electronic orders for buying or selling stocks could not reach the floor of the exchange. Such orders were rerouted while the problem computer was taken out of service for repairs.

Exchange officials said they were trying to pinpoint why the software failed. They said the problem was unrelated to Friday’s record trading volume.

The exchange did not announce a delay in trading until an hour before the scheduled opening. Officials said they waited because they were still determining the extent of the problem. Trading resumed at 10:30 a.m., an hour after the session’s scheduled start.

It was the first delay in the NYSE’s 9:30 a.m. opening since Dec. 27, 1990, when an electrical transformer blew up outside the exchange’s computer processing unit at 55 Water St. in lower Manhattan. Trading resumed that day at 11 a.m.