Elon Musk was in federal court on Monday, defending a 2018 tweet that suggested he was taking Tesla private, which went viral across investing circles.

Musk testified that the Public Investment Fund of Saudi Arabia had “unequivocally wanted to take Tesla private.” The trial concerns whether his 2018 tweet about receiving funding from the Saudis to take Tesla private at $420 caused investors to lose billions of dollars, according to The New York Times.

The judge overseeing the case already ruled that some of Musk’s statements about taking Tesla private were untrue, including his tweet that he had “funding secured” for the transaction. 

Musk said that officials from the Saudi sovereign wealth fund had yet to sign documents committing to a deal and had not discussed how much they would invest. 

“The exact amount would not be knowable without knowing who else would participate,” he said. Musk said he believed “if they say they’re going to do something, they do.” 

Before his tweet, the Saudi fund held a 5% stake in Tesla. His legal team unsuccessfully tried to subpoena the fund’s employees to testify in the trial. Lawyers for the fund argued the subpoenas were “legally deficient” and “frankly, frivolous,” according to The New York Times. 

He followed his original tweet by saying, “Investor support is confirmed. Only reason why this is not certain is that it’s contingent on a shareholder vote.”

Tesla’s stock price rose after the tweet but fell after the deal did not go through. Musk’s take-private price also came into question, and he was asked if he set the price for Tesla stock at $420 per share because it would be “a joke your girlfriend would enjoy,” likely referring to a 2019 tweet in which Musk had said, “Whoa … the stock is so high lol,” when the stock price hit $420 per share. The number is widely used to reference marijuana. 

Mr. Musk responded, “There is some karma around $420, though I should question whether that is good or bad karma at this point.” 

Musk defended the price, saying it was not a joke and that it was 20% more than Tesla’s stock price at the time. 

Lawyers for the investors said people made decisions about their investments in Tesla because Musk said he had received funding to take Tesla private. Tesla’s lawyers said it is possible investors made decisions based on Musk’s statement that he was considering taking the company private, a statement his lawyers claim was true, according to The New York Times. 

Musk denied that his social media posts were causing wild swings in Tesla’s share price. Before his tweet about taking the company private, Musk said his friends suggested he take a break from Twitter.

In 2018, he and Tesla settled a separate lawsuit with the S.E.C. regarding the tweet. The company paid a $20 million fine to the S.E.C., and Musk was forced to resign as chairman.