The Tokyo Stock Exchange has blamed a faulty data distribution server for the suspension of trading in the shares of 241 companies this morning at the peak of the Q3 earnings reporting season.
Trading in companies, including blue-chips such as Sony and Hitachi, was unavailable until 12.30pm local time in what was the worst outage to hit the bourse for six years.
A problem developed at a server supplied by Fujitsu overnight and automatic back-ups failed, Hiroaki Uji, TSE director told Bloomberg. The cause has not been determined but Uji ruled out cyber-terrorism.
The issue meant that the Sapporo Stock Exchange and Chi-X Japan were also unable to trade the affected stocks.
The outage has infuriated traders unable to react to yesterday's news from Sony which posted a third quarter net loss of over $2 billion and replaced CEO Howard Stringer.
Concerns have also been raised over the TSE's proposed merger with the Osaka Securities Exchange, with a spokesman telling Bloomberg: "We may need to review our system carefully before merging with TSE."
In 2005 the Tokyo bourse blamed Fujitsu for a similar outage, with executives from both firms taking significant pay cuts as a result.
TSE's Biggest Glitch Since '06 Casts Shadow Over Osaka Bid - Bloomberg