Euronext said on Thursday its cash and derivatives market indices were not trading due to a technical incident, and that the opening was delayed until further notice.
"We are currently addressing the root cause of this incident. Trading and order entry are allowed and market data dissemination is correct," Euronext said in a statement.
The company told CNBC that it was unable to predict when index calculations will be restored with engineers having worked on the glitch for the last two hours. Individual stocks are trading and updating normally, it added.