Meta CEO Mark Zuckerberg once considered separating Instagram from its parent company due to worries about antitrust litigation, according to an email shown Tuesday on the second day of an antitrust trial alleging Meta illegally monopolized the social media market.

In the 2018 email, Zuckerberg wrote that he was beginning to wonder if “spinning Instagram out” would be the only way to accomplish important goals, as big-tech companies grow. He also noted “there is a non-trivial chance” Meta could be forced to spin out Instagram and perhaps WhatsApp in five to 10 years anyway.

He wrote that while most companies resist breakups, “the corporate history is that most companies actually perform better after they’ve been split up.”

Asked Tuesday by attorney Daniel Matheson, who is leading the antitrust case for the Federal Trade Commission, which incidence in corporate history he had in mind, Zuckerberg responded: “I’m not sure what I had in mind then.”

Zuckerberg, who was the first witness, testified for more than seven hours over two days in the trial that could force Meta to break off Instagram and WhatsApp, startups the tech giant bought more than a decade ago that have since grown into social media powerhouses.

While questioning Zuckerberg on Tuesday morning, Matheson noted that he had referred to Instagram as being a “rapidly growing, threatening, network.” The attorney also pointed out Zuckerberg’s referring to trying to neutralize a competitor by buying the company.

But Zuckerberg said while Matheson was able to show documents in court that indicated his concern about Instagram’s growth, he also had many conversations about how excited his company was to acquire Instagram to make a better product.

Zuckerberg also said Facebook was in the process of building a camera app for sharing on mobile phones, and he thought Instagram was better at that, “so I wanted to buy them.”

Zuckerberg also pushed back against Matheson’s contention that the reason for buying the company was to neutralize a threat.

“I think that that mischaracterizes what the email was,” Zuckerberg said.

In his questioning of Zuckerberg, Matheson repeatedly brought up emails — many of them more than a decade old — written by Zuckerberg and his associates before and after the acquisition of Instagram.

While acknowledging the documents, Zuckerberg has often sought to downplay the contents, saying he wrote them in the early stages of considering the acquisition and that what he wrote at the time didn’t capture the full scope of his interest in the company.