Three stock exchanges zapped by computer glitches

Computerworld - Three of the world's largest stock exchanges suffered from unrelated computer problems this week during a period of particularly heavy trading.
The London Stock Exchange was hardest hit, with an eight-hour outage yesterday (see story). The exchange opened at 3:45 p.m. Greenwich Mean Time, rather than the usual 8 a.m. Because of the glitch, trading hours were extended from 4:30 p.m. to 6:30 p.m.
The problem was caused by the network that takes real-time price and other information from the central trading systems to market users, said Gavin Casey, chief executive of the London Stock Exchange, in a statement released Wednesday.
The shutdown occurred on the last day of the British tax year — a time when many British investors engage in heavy trading to avoid capital gains taxes — and just hours after violent market swings in the U.S.
Also on Wednesday, a system glitch at the Toronto Stock Exchange prevented trading between 4 p.m. and 4:30 p.m. At 4 p.m., closing prices are fixed, but traders still have half an hour to buy and sell stocks at those prices to execute unfinished trades.
The exchange's computer system instead shut down at 3:58 p.m., and although the problem was immediately fixed, officials decided to cancel the extra half hour of business because the closing prices didn't reflect the last two minutes of a normal trading day.
"It was a (systems) software issue," said Toronto exchange spokesman Steve Kee. As of Thursday afternoon, however, the exact cause of the problem had not been determined.
The Nasdaq Stock Market was able to keep functioning all week, although it experienced an hour-long slowdown as a result of high trading volumes and system capacity problems on Tuesday (see story).
It has been a volatile week for stock trading: Nasdaq processed a record 6.5 million quote updates Tuesday, compared with the previous record of 5.8 million.
Nasdaq's record volumes caused the slowdown of its SelectNet order management system. A spokeswoman said technical changes should make it easier to handle such volumes in the future.