The tech world’s most consequential feud has flared up again. Elon Musk and Bill Gates, two men who have shaped the modern world, are locked in a bitter public dispute, this time over foreign aid cuts with life or death stakes. The conflict pits Musk, in his role spearheading a government efficiency initiative, against Gates, the world’s most prominent philanthropist.

A little over a month after Musk’s departure from his role in the Trump administration, where he led efforts to slash federal spending, Gates took to X, Musk’s own social network, to condemn the devastating impact of those cuts on global health.

Gates Lays Out the Stakes

Drawing on new reports, Gates presented a grim tally of the human cost. “A study in the Lancet recently looked at the cumulative impact of reductions in American aid. It found that, by 2040, 8 million more children will die before their fifth birthday,” Gates posted on July 3, linking to the medical journal’s study.

He followed up by highlighting the threat to HIV treatment programs. “According to a @UNAIDS analysis, ending PEPFAR-supported programs for people living with HIV could result in an additional 4.2 million deaths by 2029,” Gates stated, providing a link to the report.

Driving the point home, he warned that pulling vaccine funding would have catastrophic results. Gavi, the Vaccine Alliance, has helped immunize over 1.1 billion children since 2000. “The U.S. announced that, after this year, it’s pulling out all its money,” Gates wrote. “If that happens, Gavi estimates that 75 million children will miss vaccinations over the next five years—and of those, 1.2 million children will die.”

His conclusion was blunt: “The facts are simple and devastating: Aid cuts have already cost lives, and the number of deaths will continue to rise.” Gates argued for a reversal, noting that global health is a tiny fraction of the federal budget. “In 2023, the US spent less than one percent of the federal budget on lifesaving global health programs.”

Musk Fires Back

While Gates never mentioned Musk by name, the world’s richest man felt targeted and seized on another user’s post to launch a counterattack. The user blasted Gates, writing, “Bro, you are worth $117 billion. If you really think aid cuts are costing lives, feel free to make up the difference.”

Musk’s reply was a single, cutting word: “Exactly.”

He then added a personal jab, dismissing Gates’s philanthropic motives. “The real reason Gates is unhappy is that HIS organization isn’t getting billions in US taxpayer money anymore.”

Exactly.

The real reason Gates is unhappy is that HIS organization isn’t getting billions in US taxpayer money anymore.

— Elon Musk (@elonmusk) July 6, 2025

As of July 5, Musk’s net worth is estimated at $361 billion by the Bloomberg Billionaires Index, while Gates’s fortune sits at $124 billion.

The Grudge: It’s Always About Tesla

The animosity between Musk and Gates is not new. It stems from a deep grudge Musk holds over Gates for shorting Tesla stock. Think of short selling as betting on failure. A short seller borrows shares of a stock, immediately sells them, and waits for the price to crash. If it does, they buy the shares back at the new, lower price, return them to the lender, and pocket the difference. It’s a high risk move that infuriates founders like Musk, who see it as a direct attack on their company. Shorting is not illegal, but it’s one of the most aggressive moves you can make in the market.

Musk has never forgotten Gates’s bet against his electric car company and brings it up frequently.

“Gates placed a massive bet on Tesla dying when our company was at one of its weakest moments several years ago,” Musk posted in September 2023. “Such a big short position also drives the stock down for everyday investors.”  He then added, “To the best of my knowledge, Gates still has that massive bet against Tesla on the table. Someone should ask him if he does.”

Just so that the public understands:

Taking out a short position against Tesla, as Gates did, results in the highest return only if a company goes bankrupt!

Gates placed a massive bet on Tesla dying when our company was at one of its weakest moments several years ago. Such a…

— Elon Musk (@elonmusk) September 11, 2023

While Gates has acknowledged placing a short position on Tesla in the past, he has never publicly confirmed if the position is still active, leaving the door open for Musk to continue fueling the feud.