The technical issue occurred during the last 30 minutes of Monday’s session, when orders couldn’t be matched, the Ho Chi Minh City Stock Exchange said in a statement. The day-long halt means that companies including Vietnam Dairy Products JSC, PetroVietnam Gas JSC and VietJet Aviation JSC are all unavailable to investors. The bourse has averaged $319 million worth of trading each day over the past month, according to data compiled by Bloomberg.

The halt didn’t seem to dampen sentiment in the rest of the $170 billion Vietnamese market. The Hanoi Stock Exchange HNX Index was up as much 2.5 percent to its highest level since October 2010, while the Unlisted Public Company Market rose 1.3 percent to its best mark since November 2016. The VN-Index is up 58 percent in the past year, and gained 10 percent in 2018.

“The Ho Chi Minh City Stock Exchange has been working with experts from Thailand’s stock exchange to investigate the reason for the technical issue and resolve the problem, and we really hope the trading will be resumed Jan. 24,” State Securities Commission Chairman Tran Van Dung said in an emailed statement.

Outage Duration

David Shin, Asia head of global equity derivative sales at TD Securities in Singapore, said that while emerging-markets investors expect risks, the duration of the outage caused him to lose confidence in the exchange’s support teams. “I wonder how much foreign money flow left off the back of this,” he said.

As well as the Hanoi and Upcom stock venues, Vietnam’s derivatives market was also open as usual, the regulator said in a separate statement. Dung said investors should be “cautious” when trading derivatives because there will be no prices for the underlying stocks of the VN30 Index. The nation started stock-index futures trading in August.

“Technical issues happen at most exchanges around the world, but are usually fixed within one day,” said Michel Tosto, head of institutional sales and brokerage at Viet Capital Securities JSC. “If the issue persists beyond today, I think people will start asking a lot more questions.”

The Ho Chi Minh City bourse experienced a malfunction in August that briefly affected data distribution.

“I have seen more acceptance rather than anger, at least what’s directed to our side,” said Tyler Cheung, director of institutional clients at ACB Securities JSC in Ho Chi Minh City. “Nothing we can do about it from the broker perspective.”

By Giang Nguyen & Andrea Tan - Bloomberg - January 23, 2018