Bill Gates, co-founder of software giant Microsoft (MSFT), is on the counterattack.
His adversary is not just anyone. It is Elon Musk, the charismatic CEO of Tesla (TSLA) who has promised to save the planet from pollution and conquer Mars with his other company SpaceX.
Musk has become in recent months the world's most influential CEO, with more than 90 million followers on Twitter (TWTR), the social network he is in the process of acquiring for $44 billion.
The serial entrepreneur has become a disruptor who likes to bend the rules and shake up his peers in tech. Nothing seems to scare him, neither the name nor the punching power of the opponent.
So a few days ago, Musk, the richest man in the world, questioned the environmental qualifications of Gates, formerly the richest man in the world.
Musk accused Gates of having dealt a blow to his own fight for environmental protection by shorting Tesla stock.
Cruel Joke
Selling stock short is a bet that the stock's price will drop.
"Sorry, but I cannot take your philanthropy on climate change seriously when you have a massive short position against Tesla the company doing the most to solve climate change," Musk recently wrote to Gates. It was the end of a discussion the two billionaires were having about working together for common causes.
The mogul later accompanied his criticism with an unflattering and cruel tweet aimed at Gates.
Gates let a few days pass and just responded to Musk.
"I don't think that whether one's short or long Tesla is a statement about your seriousness about climate change," the billionaire said during The Wall Street Journal's CEO Council Summit on May 4. "I'm putting billions of dollars into climate-change innovation, I applaud Tesla's role in helping with climate change."
Gates added that he has "nothing but positive things to say about" Musk.
"If he makes Twitter worse, fine, I'll speak out about that, but I wouldn't assume that's what's going to happen," Gates added.
In a separate interview with the BBC, Gates also pushed back against Musk's charge against his environmental credentials.
"The popularity of electric cars will lead to more competition for selling those cars. So there's a difference between electric cars being adopted, and companies becoming infinitely valuable," Gates said.
Basically, his short position against Tesla has nothing to do with the environment but with the fact that Tesla is evolving in a sector that will become hypercompetitive. That's not positive for the world leader in electric vehicles.
Before ending the exchange with Gates, Musk said he asked his peer billionaire if he still had his $500 million short position against Tesla.
Gates reportedly replied that he hadn't closed it yet. It was this response that angered Musk. The billionaire is known for his disdain for short sellers and especially Tesla short sellers.
Some investors who bet on Tesla stock slumping, like hedge-fund heavyweight David Einhorn of Greenlight Capital, have paid a serious price when the stock price jumped instead.
Musk and Gates Sparred over Covid, Crypto
Musk literally had shorts delivered to Einhorn in 2018, when Tesla was on the brink of the financial abyss.
"I want to thank @elonmusk for the shorts," Einhorn posted on Twitter on August 2018 with a photo of the shorts. "He is a man of his word! They did come with some manufacturing defects. #tesla."
"Put them on & post a selfie," Musk replied.
"There is no need for him to be nice to me," Gates said during the BBC interview.
The two billionaires, who are big donors to environmental causes, have often clashed on different topics such as the pandemic and cryptocurrencies.
In February 2020, during an interview with Youtuber Marques Brownlee, Gates notably said he bought a Porsche Cayman, while acknowledging that Tesla had contributed to the adoption of electric vehicles.
Tensions between the two have flared regarding the pandemic. Gates did not back Musk's playing down the severity of the virus and strong criticism of stay-at-home measures.
In the face of Gates's criticism of his statements related to the pandemic, Musk tweeted posts that were not very flattering toward Gates.
Gates also warned people who want to invest in bitcoin -- as Tesla did in February 2021. Musk is a crypto evangelist.
"Elon has tons of money and he's very sophisticated, so I don't worry that his bitcoin will sort of randomly go up or down," Gates said during an interview with Bloomberg.
"I do think people get bought into these manias, who may not have as much money to spare, so I'm not bullish on bitcoin, and my general thought would be that, if you have less money than Elon, you should probably watch out," Gates warned.