The SIX Swiss Exchange experienced its worst outage in more than a decade on Tuesday, when trading came to a standstill for three hours due to a technical issue.

We can “definitely rule out that it was a hack,” said Juerg Schneider, the exchange’s head of media relations, without giving details about the nature of the technical problem. A post-mortem will be released in a couple of days, he added.

The bourse is ensuring “this doesn’t happen again, I am sure internally there will be measures to try to avoid this in the future,” he said.

Trading was interrupted shortly after 11 a.m. local time and didn’t resume until 2 p.m.

Several similar events on other venues, including the New York Stock Exchange, in recent years have sparked a renewed focus from regulators globally on what protocol to follow in these cases.