Billionaire Bill Gates mentioned to author Walter Isaacson that Elon Musk became "super mean" to him after learning he had taken a short position on Tesla stock.

Isaacson, who has been penning a biography on Musk for the last three years, provides further insight into this episode in a segment from the forthcoming book.

"Once he heard I'd shorted the stock, he was super mean to me, but he's super mean to so many people, so you can't take it too personally," Gates told the author, Fortune reported.

In April 2022, Musk confirmed that he had declined a philanthropy request from Gates due to the stock shorting episode, revealing portions of their text conversation.

In the exchanged messages, the two seemed to arrange a meeting, when Musk inquired if Gates still maintained a "half billion dollar short position against Tesla."

"Sorry to say I haven’t closed it yet," adding in another text. "I would like to discuss philanthropy possibilities."

Musk responded that he couldn't take Gates' request "seriously when you have a massive short position against Tesla, the company doing the most to solve climate change."

Gates told Isaacson that he apologised to Musk, but the relationship has not improved.

After revealing the text exchange, Musk shared a meme that seemed to poke fun at Gates' physique. However, he shortly declared that he was moving on from the topic.

in case u need to lose a boner fast pic.twitter.com/fcHiaXKCJi

— Elon Musk (@elonmusk) April 23, 2022