Elon Musk tweeted that he confronted Bill Gates about short selling Tesla

Microsoft co-founder Elon Musk accused Bill Gates of selling Tesla.

In a tweet Friday, the Tesla CEO admitted that he asked Gates if he was short selling shares of the electric car maker. When investors sell shares, they are betting that the price of the asset will fall.

“I heard from several people at TED that Gates still has half a billion dollars for Tesla, which is why I asked him, so it’s not so secret,” Musk said in a tweet.

He was responding to a question from a Twitter user About whether a screenshot of a supposed text conversation between billionaires is real.

The Tesla boss’ response was, “Yes, but I didn’t leak it to the New York Times. They must have gotten it through friends of friends.”

In a text exchange, which cannot be independently verified by CNBC, Mask Gates asked: “Do you still have a half-billion dollar short position against Tesla?”

Gates replied, “I’m sorry to say I didn’t close it. I’d like to discuss the possibilities for philanthropy.”

Musk replied, “Sorry, I can’t take your philanthropy seriously when you have a massive short position against Tesla, the company that is doing everything it can to solve climate change.”

A spokesman for Bill Gates was not immediately available for comment when contacted by CNBC.

“It’s important to say that what Elon did with Tesla is one of the biggest contributions to climate change ever,” Gates told New York Times opinion writer Kara Swisher last year. “You know, downplaying Elon is not a good idea.”

But he added that what Tesla does are “easy things, like passenger cars.” Gates stressed the need to make a greater impact on climate change by tackling other industries.

“We’re basically not doing enough of the hard stuff: steel, cement, meat,” he said at the time. “And unfortunately, the things people think about – electricity, passenger cars – are one-third of the problem. So we have to work on two-thirds.”

“If all you care about is those short-term metrics, not the green premiums across the board, you’re missing out on what’s the longest lead, the hard stuff.”

This isn’t the first time the two men have publicly disagreed.

When Gates revealed in 2020 that he had bought himself an all-electric Porsche Taycan, one Twitter user asked, “I wonder why Bill Gates decided to go with the Taycan instead of the Tesla.”

Musk responded in a tweet: “My conversations with Gates have been disappointing [to be honest]. ”

Musk also previously speculated that Gates might short sell his company’s shares. Asked about those comments and whether he fell short on Tesla, Gates told CNBC last year: “I’m not talking about my investments, but I think he should be very proud of what he’s done.”

Also in a Bloomberg interview in February 2021, Gates said he wished he was “on the long side” of Tesla when asked about Musk’s allegations.

CNBC’s Todd Haselton and Ryan Brown contributed to this report