Meta CEO Mark Zuckerberg took the stand Monday, as his social media company faces off against the Federal Trade Commission (FTC) in a case that could determine the fate of the tech titan’s empire. 

The FTC called Zuckerberg as its first witness, as it seeks to show that Meta acquired Instagram and WhatsApp to further entrench and protect its monopoly over personal social networking. 

In opening arguments Monday morning, the agency argued Facebook’s parent company was struggling to compete in the early 2010s as consumers moved away from websites to mobile apps. 

As apps like Instagram and WhatsApp grew in popularity, Meta initially attempted to offer similar products before ultimately acquiring the apps for $1 billion and $19 billion, respectively. The FTC described this as a push to neutralize its competitors. 

“The reason that we’re here is that for more than 100 years, American public policy has insisted that firms must compete if they want to succeed,” Daniel Matheson, the lead attorney representing the FTC, said in opening remarks Monday. “Meta broke that deal.” 

The agency has sought to separate Meta’s platforms from other social media apps, such as TikTok and YouTube, by arguing that Facebook and Instagram are centered on connecting friends and family. The other main competitor in this market is Snapchat, according to the FTC. 

Meta contends it is not a monopolist and faces direct competition from TikTok, YouTube and numerous other platforms. 

“This case is a grab bag of FTC theories at war with facts and at war with the law,” said Mark Hansen, Meta’s lead attorney. “The FTC wants you to believe this case is all about friends and family sharing.” 

However, he argued, “the facts are different.”