Swiss stock exchange probes three-hour trading blackout

"Three hours is a lifetime on a trading day," said one trader about the stock market outage. © Keystone / Ennio Leanza

The SIX Swiss Exchange is investigating Tuesday’s technical glitch that caused the country's worst stock market outage in more than decade. 

The Zurich-based exchange said it will release findings from its investigation in a couple of days. 

“It was a technical issue,” said Jürg Schneider, the Swiss exchange’s head of media relations, without giving details about the specific nature of the problem. We can “definitely rule out that it was a hack,” he said, adding that it was the first such disruption since 2012. 

Trading in stocks and derivative instruments was interrupted shortly after 11am local time on Tuesday and didn’t resume until 2pm. The fault brought the Swiss Market Index to a grinding halt, affecting trading in some of Europe’s largest companies such as Nestle SA and Roche Holding AG. With the US consumer price inflation data ahead, it caused frustration among traders.

“It felt like it lasted for ages, three hours is a lifetime on a trading day, especially on US CPI day,” Ipek Ozkardeskaya, senior analyst at Swissquote Bank said. “You can’t do anything and that’s frustrating.”

Such technical outages have hit other stock exchanges in recent years from New York to Tokyo. In October 2020, trading in all stocks and derivatives on Euronext NV markets shut down for three hours, the same year the German operator Deutsche Boerse AG was hit by two major outages.

Computer malfunctions triggered wild price swings and trading halts on the New York Stock Exchange earlier this year.

The benchmark SMI Index contains the 20 largest and most liquid companies listed on the Swiss stock exchange, including two of Europe’s top five biggest companies by market capitalisation.

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