Meta CEO Mark Zuckerberg considered spinning out Instagram in 2018 on concerns about the rising threat of antitrust litigation against Facebook, according to an email presented Tuesday in a Washington, D.C. courtroom.

During Zuckerberg’s second day of testimony in Meta’s antitrust trial with the Federal Trade Commission, lawyers representing the FTC presented an email from May 2018, in which Zuckerberg appeared to comment on the possibility of separating the photo-sharing app his company purchased in 2012 for $1 billion. In 2012, Instagram had fewer than 10 employees while Facebook, prior to its corporate rebranding to Meta, was approaching its initial public offering.

“And i’m beginning to wonder whether spinning Instagram out is the the only structure that will accomplish a number of important goals,” Zuckerberg wrote in the email. “As calls to break up the big tech companies grow, there is a non-trivial chance that we will be forced to spin out Instagram and perhaps WhatsApp in the next 5-10 years anyway. This is one more factor we should consider.”

Meta’s acquisition of Instagram and its ensuing 2014 purchase of WhatsApp for $19 billion are at the heart of the blockbuster antitrust trial that kicked off Monday and could last weeks.

The FTC alleges that Meta monopolizes the personal social networking market, and believes that the company should never have been able to acquire the photo-sharing and messaging apps. The commission is seeking to cleave those apps from Meta as a possible remedy.

Meta disputes the FTC’s allegations and claims the commission mischaracterizes the competitive landscape and fails to acknowledge a number of rivals like TikTok and Apple’s iMessage.

WATCH: Mark Zuckerberg takes witness stand on first day of antitrust trial.