By Suryatapa Bhattacharya and Chieko Tsuneoka 

TOKYO -- The Tokyo Stock Exchange said it would resume normal trading Friday after an unprecedented all-day shutdown Thursday that executives blamed on a malfunctioning computer part.

"I keenly feel my responsibility as someone overseeing markets," said Koichiro Miyahara, chief executive of the stock exchange, which is operated by Japan Exchange Group Inc. "We will conduct an exhaustive examination into the cause."

The exchange's chief information officer, Ryusuke Yokoyama, said the machines involved weren't connected to the outside and there was no evidence of hacking.

At 7:04 a.m. Thursday Tokyo time, a magnetic-disk device used to store trading information malfunctioned, and a switchover to a backup device didn't work, the exchange said. That left it unable to transmit price information properly.

Officials said a quicker resumption of trading might have been possible by restarting the system, but they feared disruption if accumulated orders suddenly flooded the market. They said it was safer to call off the entire day of trading Thursday, cancel orders that had been waiting before the market opened and make a fresh start Friday.

Assuming Friday's trading proceeds as planned, market participants said they didn't expect long-term disruption to the market, but the shutdown was an embarrassment for a financial capital that has been looking to play a bigger role in Asian markets as concerns grow about Hong Kong's future.

At a news conference, Mr. Miyahara, the exchange CEO, was asked about the slogan of "Never stop" that the exchange and technology provider Fujitsu Ltd. had promoted when introducing upgrades in 2015. In response, he repeated an apology for causing market participants trouble. A Fujitsu spokesman referred questions to the Tokyo Stock Exchange.

Thursday's problem marked the first time an entire day of stock trading was halted in Tokyo since the exchange moved to a fully computerized trading system in 1999.

It led to some unusual scenes. Displays at the exchange, which typically processes more than a billion shares a day, showed zero volume for all market segments. Newspaper stock charts consisted simply of a series of dashes in place of prices.

The Osaka stock exchange remained open, and futures prices tied to the benchmark Nikkei stock index were up, suggesting traders didn't foresee a major disruption.

"It is good to see that emotions are not taking over for the broader markets," said Takeo Kamai, head of execution services at CLSA in Tokyo.

Write to Suryatapa Bhattacharya at and Chieko Tsuneoka at


(END) Dow Jones Newswires

October 01, 2020 08:40 ET (12:40 GMT)

Copyright (c) 2020 Dow Jones & Company, Inc.