THE Singapore Exchange (SGX) said the trading glitch that paralysed its securities and derivatives markets was the result of multiple power supply issues, affecting SGX's hardware that provides connectivity to market participants.

The outage did not arise from a cyber-attack, it noted.

"Market participants were disconnected at 1418 hours and SGX declared a formal trading halt at 1451 hours. No trades were executed between 1418 hours and 1451 hours."

It reopened its securities market at 5.15 pm to allow trading for 30 minutes.

Meanwhile, the trading of derivatives resumed at 7pm and will continue until 2am. SGX said trading in both markets was orderly and the resumption was managed, ensuring adequate market participants connectivity.

It apologised for the outage and the inconvenience caused to market participants.

"We are currently investigating the root cause for the disruption," said Tim Utama, chief operations and technology officer of SGX in a statement.

The glitch, which affected trading for almost the entire afternoon angered brokers and remisiers.

"The whole market has been at a standstill," said a trader.

Remisier Alvin Yong, said: "Brokerages aren't likely to be too happy about this because they are losing commissions. SGX may lose some clearing fees as well. This is a slight blow to its aspiration to be a world class exchange. They shouldn't have have to call for an industry standstill to trading."

One broker said the extent of the problem became evident only slowly.

"Initially, we thought it was just us. We alerted the backroom and when they investigated, realised other brokerages didn't have access to the markets as well.

"But we feel better because other brokerages are having the same problem, which means, everybody can't trade. But we will lose commission fees because our fees rely on volume as well," the broker said.