Elon Musk testified that Saudi Arabia's sovereign wealth fund “unequivocally” wanted to take Tesla Inc. private in 2018, a core element of his defense to claims that his tweets about the take-private plan misled shareholders.

The shareholders contend in a class-action lawsuit that the tweets were lies that cost them big losses from wild stock price swings over a 10-day period before the plan was abandoned.

As he resumed testifying Monday after a brief appearance on the witness stand Friday, Musk told jurors that he had discussions with the Saudi Public Investment Fund about the transaction. He said the amount required for the fund was “potentially” less than US$10 billion. Court filings indicate that Musk himself owned about 19 per cent of Tesla at the time. The billionaire would have needed more than 50 per cent to take the company private.

“The thing that was absolutely unequivocal is that they were absolutely supportive of taking Tesla private,” Musk said in San Francisco federal court. “Unequivocal, without hesitation.” The PIF’s governor, Yasir Al-Rumayyan, had checked with Saudi Arabia’s Crown Prince, Musk said. “I took that to mean it was a done deal.”

Nicholas Porritt, a lawyer for the investors, prodded Musk with questions about why there was nothing in writing and no details on the specific amount that the PIF would pony up.

“That’s not really how they do business,” Musk said. “If they say they’re going to do something they do. A signed document is neither here nor there.”

The trial requires jurors to delve into Musk’s state of mind when he tweeted on Aug. 7, 2018, that he had “funding secured” to take Tesla private at US$420-a-share and added that “investor support is confirmed.”

Musk’s lawyers told the jury during opening statements last week that while his tweets were rushed and contained technical errors, they accurately conveyed that he was sincere about taking Tesla private. 

In his testimony Friday, the renowned entrepreneur and prolific Twitter user offered a remarkably modest assessment of his influence on the social media network that he now owns: “Just because I tweet about something doesn’t mean people believe it or will act accordingly.” The testimony showed Musk minimizing his role in the electric car-maker’s surging stock price after he tweeted.