SINGAPORE - It was largely business as usual on the trading floor on Friday (July 15) as the stock market reopened after the massive outage that hit the Singapore Exchange a day earlier.

All systems appeared to be operating normally, while the benchmark Straits Times Index rose at the open in line with gains at other regional bourses.

But some investors had to swallow losses as they missed trading opportunities on Thursday, remisiers told The Straits Times.

"As far as I can tell, everything - the orders, the messaging - is working at 100 per cent, but in terms of trading the clients who wanted to sell yesterday are having to do so at a lower price now," remisier Soh Wee Boon said.

"For instance, there's one who wanted to sell her Ezion shares yesterday when it went up, but now it's down by over one cent since open," he added. Ezion has pared 4.6 per cent to 41.5 cents by 10.20am.

The STI has however put on 1 per cent to 2936.01, joining Shanghai, Hong Kong and Tokyo in taking the cue from Dow Jones' 0.73 per cent gain overnight.

Another remisier, who requested anonymity, said seeing the systems back to normal is hardly any relief.

"Now the issue is to see how we can assist our clients, especially those who had a short position and couldn't get out yesterday," he said. "I have heard that the SGX may allow these people to buy for the cover today without suffering losses, but there's no official word yet."

Thursday's outage lasting five hours and 10 minutes was the longest trading disruption the SGX has faced so far, raising fresh concerns over the resilience of its systems despite the many million invested into tech capabilities in recent years.

SGX shares opened down 4 per cent on Friday but recovered to trade up 0.13 per cent to $7.80 as at 10.20am.

Meanwhile, Noble Group were trading down 0.6 per cent to 16.5 cents. The commodity firm was able to extend the deadline for the rights trading of its ongoing share issue exercise to 5pm on Friday.