On December 9, the U.S. Federal Trade Commission sued Facebook, alleging the company has illegally maintained a “personal social networking monopoly through a years-long course of anticompetitive conduct.” The lawsuit could require the divestment of Instagram and Whatsapp from Facebook, among other prohibitive measures.

“Obviously we disagree with the accusations,” said Instagram head Adam Mosseri in a story posted to the app and on Twitter. “The FTC cleared the acquisition of Instagram more than eight years ago.” Facebook bought Instagram for $715 million in 2013 and Whatsapp for $22 billion in 2014—acquisitions that were approved by regulators at the time.

“Facebook is going to fight a breakup with everything it’s got,” said Sarah Frier, Bloomberg social media reporter and author of No Filter, in a tweetAccording to Frier, while each social app seems distinct to users, they share an integrated backend that will prove difficult to dismantle.