CALCULATION of Japan’s benchmark stock market indices froze yesterday after a computer glitch, the latest in a string of technical problems to hit the country’s exchange.
Although individual share sales were unaffected, a system error caused the Nikkei share average, which includes the headline Nikkei 225 stock average, to stop in early afternoon trade. The calculation of the size of the stock market is usually updated once a minute. The error was related to power failures across Tokyo earlier in the day.
Nihon Keizai Shimbun, the publisher that compiles the index, said later that the average finished up 1.88 per cent, or 292.09 points, at 15,857.11, its best close since May, despite the upset.
However, the halt in the calculation of the benchmark kept some market participants from trading actively and helped to further reduce trading volume, in a market that is often thin at the peak of the summer holidays. Trading volume yesterday fell by more than 20 per cent from Friday.
Noboru Yoshioka, general manager of the electronic media bureau at the publisher, said that he was “99 per cent” sure that the system would be back to normal at the start of trading today, but could not give a complete guarantee that the problem would be fixed.
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A previous technical hitch at the Tokyo Stock Exchange caused the bourse to halt trading for almost a full day last November.
In December, the exchange’s computer systems failed to cancel a mistaken order to sell 610,000 shares for 1 yen, instead of one share for Y610,000. The slip-up cost Mizuho Securities, a brokerage firm, about Y40 billion (£182 million) and led to the resignation of Takuo Tsurushima, the exchange’s president, and two other directors. In January a flood of sell orders nearly flooded the exchange’s system and forced it to close early. It then shortened trading hours for three months.
A spokesman for Daiwa Securities Group, Japan’s second-largest brokerage, said that it had its own computer system to calculate the Nikkei average, but retail investors might have been more affected.
Traders earlier had reported problems with some computer systems owing to the power cuts, which affected about 1.4 million homes.
Mr Yoshioka said that the company had switched to its in-house generating system at the time of the early morning power cuts, but this system went down in the early afternoon because its capacity was about six hours.
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There is a back-up system to calculate the Nikkei average, but an error occurred when it tried to switch to the system, he said. The company is still investigating further details of the cause.