Britain’s Competition and Markets Authority (CMA) will block Microsoft’s $69 billion acquisition of Blizzard, Reuters reports. The reason for the measures are concerns that it will hamper competition in cloud gaming, dealing an unexpected blow to the biggest deal in gaming.

The country’s antitrust regulator said Microsoft’s commitment to offer access to Activision’s multibillion-dollar “Call of Duty” franchise on leading cloud gaming platforms would not effectively address its concerns.

Activision CEO Bobby Kotick told employees that this isn’t the news the companies wanted, but it’s only temporary.

“We will be reviewing our UK growth plans. Global innovators large and small will take note that – for all its rhetoric – the UK is apparently closed for business”,

the company said in a separate statement.

Shares of Activision, which also produces the games “Candy Crush,” “Overwatch” and “World of Warcraft,” fell 12 percent to $76.65, moving away from Microsoft’s offer price of $95 a share. If the losses persist, the video game publisher will have to remove nearly $8 billion from its market valuation.

“We expect that Microsoft will continue to fight this”,

Evercore ISI analyst Kirk Materne said in a note.

If Microsoft opts out it would free up more than $60 billion in cash flow that could be returned to investors or invested in AI-related offerings, he noted.

The Activision deal is the biggest tech-related deal the Competition and Markets Authority (CMA) has blocked, the latest sign that the British watchdog is ready to crack down on big tech after it blocked Facebook-owner Meta’s acquisition of Giphy in 2021.

Europe is expected to make a decision on the Activision deal by May 22. That’s not the only problem facing the tech giant and the franchise, as the US Federal Trade Commission is also trying to block it.