Trading on the Tokyo Stock Exchange has been suspended because of a problem with the system for relaying market information.
The stock exchange said all trading was stopped because of the issue and will not resume for the rest of the day.
It was unclear when it would be resolved and the system would be operating again.
Japan’s nationally circulated Asahi newspaper, without citing sources, said the cause was probably a mechanical failure.
The Tokyo Stock Exchange is the world’s third largest bourse after the New York Stock Exchange and Nasdaq, with market capitalisation of nearly six trillion dollars.
Previous outages occurred when the “arrowhead” system created by Fujitsu to handle its electronic trading became overwhelmed with too many orders at one time.
That is what happened on October 9 2018, according to a release on the TSE’s website.
But during that disruption, some backup systems for trading continued to function.
The exchange promised to investigate, conduct malfunction tests and change the system to ensure that a flood of orders would not cause the entire system to stop working.
Several top executives of the exchange were penalised.