Elon Musk began testifying today in the jury trial over whether his false tweets in 2018 about taking Tesla private caused investors to lose billions of dollars.

During testimony in a federal courtroom in San Francisco, Musk denied that his tweets cause Tesla’s stock price to go up or down. “Just because I tweet something does not mean people believe it or will act accordingly,” Musk said in response to a question from attorney Nicholas Porritt, who represents investors in the class-action lawsuit against Musk.

“It’s difficult to say that the stock price is linked to the tweets. There have been many cases where I thought if I were to tweet something that the stock price would go down,” the Tesla CEO said on the witness stand.