Shanghai Stock Exchange restores pricing of CSI 300 Index after glitch caused by system upgrade led to wild swings

A technical glitch that caused erroneous pricing of the CSI 300 Index and at least two other Chinese equity gauges on Monday morning was caused by a system upgrade, according to the Shanghai Stock Exchange.

Normal pricing was restored at 1pm and metrics such as intraday highs and lows would be fixed after the market close, the bourse said in a statement on its official microblog. It apologised for the error, saying a weekend upgrade of the cross-market index calculation system was the cause of the incident.

The CSI 300 index of the biggest listed companies in mainland China added 0.4 per cent at the close, after at one point dropping 2.8 per cent in the morning session.

The CSI 1000 Index finished the day 1.6 per cent higher, after an earlier surge of as much as 6.6 per cent. An index tracking drug makers in Shanghai and Shenzhen rose 1.6 per cent having slumped at least 12 per cent in the morning, exceeding the 10 per cent daily cap imposed by the regulator.

The malfunction came at a time when investors have been flocking to Chinese stocks as a shelter from the global turmoil caused by Covid-19. China’s market is the world’s only major one that has not slipped into bear-market territory, and the CSI 300 is trading at the biggest valuation premium to emerging-market stocks in a year, as data showed an improvement in China’s economy in March.