The Tokyo Stock Exchange (TSE) was forced to suspend trading of stocks and convertible bonds for more than four hours on Tuesday morning following problems with a software upgrade.
According to local news reports, the TSE's trading capacity was increased in early October to deal with larger trading volumes, but the software was not made compatible with data alterations, which caused the trading system to malfunction.
Share trading eventually began at 1.30 pm local time, four and a half hours later then usual. A statement released by the TSE says the technical difficulties in the stock/convertible bond trading system that caused suspension of the stock trading session have been resolved.
Regional stock markets in southern Fukuoka and northern Sapporo use the same trading system and were also forced to halt trading of stocks and convertible bonds.
Japan's regulatory Financial Services Agency, which is due to make a decision on TSE's plans to list, has called for the exchange to file a formal report on the systems failure.