It happens sometimes. Usually it is when there are rumors that will have a significant impact on the stock. In that case the stock can be halted until the company gives a statement about it. I’m not sure if it is the company can halt it, I think they can request it and provide information why it should be halted and then it is up to the stock exchange to determine. And the stock exchange has its own rules for when to halt the trade.

I expect Ubisoft to update during the next week or perhaps already during the weekend and then the trading can continue.