The Hong Kong Stock Exchange was forced to suspend afternoon trading in seven listed companies after the news portion of its website was hit by hackers.
The news website, which publishes companies' regulatory filings, was inaccessible at times beginning around midday in Hong Kong, according to the Wall Street Journal.
The exchange operator emphasised that - although the news site had been hit by what appeared to be a malicious hacking - trading systems had not been breached.
The affected companies, which included HSBC, Cathay Pacific Airways and the Hong Kong Exchanges & Clearing, which runs the stock exchange, had all released price-sensitive information earlier in the day.
"Our current assessment is that this is a result of a malicious attack by outside hacking," said Charlies Li, chief executive of Hong Kong Exchanges & Clearing.
The incident is the first time the Hong Kong Stock Exchange has been forced to suspend trading for technical reasons, according to reports.
The trading halt affected stocks contributing to about 18% of the Hang Seng index's weight, according to the Bangkok Post.
The Zimbabwe Stock Exchange website was attacked by hackers last week, forcing a shutdown of the site, the paper said.