Facebook Inc. slammed the U.K.’s antitrust regulator over its provisional call that the tech giant would have to sell all of Giphy to address competition concerns, setting up a bitter fight over the completed deal. 

Selling off the company that Facebook bought last year for $400 million would be “grossly unreasonable and disproportionate,” Facebook argued in a response to the Competition and Markets Authority’s concerns published on Wednesday.

The cases open up yet another front for the world’s biggest tech firms to fight on. The European Union and Germany are already investigating Facebook’s use of personal data while the CMA is looking at its Marketplace and Dating services. In the U.S. antitrust officials refiled their monopoly lawsuit against Facebook that was tossed in June.

Facebook said regulators should carefully weigh “the intrusive step of ordering the sale of a company which does not carry on business in the U.K.” and that there are also questions on whether a global divestment can be enforced by the British authority.

The Silicon Valley firm has been fighting the CMA for more than a year over a deal it completed before seeking approval from the U.K. or other authorities. The company is in the eye of the storm as global regulators crackdown on big tech takeovers of potential smaller rivals. 

Regulators faced a barrage of criticism for allowing Silicon Valley to snap up potential rivals before they make it big. Facebook’s game-changing takeover of photo-sharing app Instagram is often cited as a deal that was waved through by regulators without proper scrutiny.

The CMA didn’t accept an offer Facebook made in March for rivals and customers to be able to access Giphy’s library on the same terms as before the deal for five years. 

The CMA didn’t immediately respond to a request for comment. 

The watchdog had taken an initial view Augus that “the only effective way to address the competition issues,” is for Facebook to sell Giphy “in its entirety, to a suitable buyer,” the Competition and Markets Authority said last month. It has set an Oct. 6 deadline for a decision on the inquiry to be made. 

—Bloomberg News

Subscribe to Ad Age now for award-winning news and insight.