Source of incident identified

Following preliminary investigations and analysis, the outage has been traced to a malfunction in the uninterruptible power supply (UPS) systems deployed at the SGX data centre. Power is supplied to the data centre from two separate substations. These sources are in turn connected to individual UPS systems providing four layers of redundancy.

Resulting from a momentary fluctuation in power supply from the substations, the UPS systems switched to its internal power source. However, the internal power source in both UPS systems malfunctioned.

Sequence of events

This malfunction affected the hardware providing market participants’ connectivity to SGX’s markets. 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.

The Securities market participants were able to re-connect starting at 1645 hours followed by a pre-opening session at 1700 hours, and the market reopened for trading at 1715 hours. Trading was extended beyond the normal trading hours to provide for the required minimum of 30 minutes of continuous trading. Securities market pre-closing session started at 1745 hours and the market closed at 1751 hours.

The Derivatives market participants were able to re-connect from 1800 hours followed by a pre-opening session at 1845 hours, and the market reopened for trading at 1900 hours. The reopening of the Derivatives market was timed to cater for the orderly resumption of “same-day” (T session) or “next-day” (T+1 session) trading according to each contract’s specifications.

Trading in both markets was orderly and the reopen was managed, ensuring adequate market participants’ connectivity.

Details on course of events

The power supply disruption was transienower supply disruption was transient in nature, bringing about a potential mismatch between the primary and secondary market order books. As such, a cut-over to the secondary data centre from the primary data centre was not executed. A complete restart of both primary and secondary systems was necessary. This step was essential to ensure continued integrity of the markets.

This recovery process was completed at 1645 hours for the securities market and 1800 hours for the derivatives market.

Remedial actions taken overnight

Further tests were successfully carried out overnight to ensure a stable power supply. In addition, contingency measures have been put in place to reduce the recovery times should there be a repeat of the UPS system malfunction.

“As a prudent market operator, we are firmly committed to investor protection and market integrity. We take seriously yesterday’s incident and remain focused on delivering the highest possible levels of service availability,” said Tim Utama, Chief Operations and Technology Officer of SGX.