Tesla chief executive Elon Musk donated a total of 5,044,000 shares in the world's most valuable automaker to a charity from Nov. 19 to Nov. 29 last year, its filing with U.S. Securities and Exchange Commission (SEC) showed on Monday.
The donation was worth $5.74 billion, based on the closing prices of Tesla shares on the five days that he donated the stocks.
The filing did not disclose the name of the charity.
Late last year, the billionaire sold $16.4 billion worth of shares after polling Twitter users about offloading 10% of his stake in the electric-car maker.
He tweeted last year that he would pay more than $11 billion in taxes in 2021 due to his exercise of stock options set to expire this year.
He also traded barbs with politicians Bernie Sanders and Elizabeth Warren who called on wealthy people to pay more taxes.
Analysts have said there would be a tax benefit for Musk potentially gifting Tesla stock. This is because shares that are donated to charity are not subject to capital gains tax, as they would be if they were sold.
"His tax benefit would be huge. He'd save between 40% and 50% of the $5.7 billion in tax, depending on whether he could take the deduction against his California income and he'd avoid the gains tax he would have to pay if he sold the stock," Bob Lord, an associate fellow at the Institute for Policy Studies who studies tax policy, said.
He said Musk might have contributed the stock to intermediaries such as "donor-advised funds", not outright to charitable groups.
Tesla was not immediately available for comment.
Musk's public philanthropy gestures have so far trailed other billionaires. Musk and Amazon.com Inc founder Jeff Bezos have donated less than 1% of their net worth, whereas Warren Buffett and George Soros had given away more than 20% of their net worth as of early September, according to Forbes.
In 2001, he set up the Musk Foundation, offering grants for the "development of safe artificial intelligence to benefit humanity" among other causes, according to its website. Musk's foundation has over $200 million in assets.
Earlier last year, Musk and his foundation offered to give $100 million prizes to those who can come up with a technology to help remove carbon from the atmosphere. He said last year he was donating $20 million to schools in Cameron County, Texas where a Space X rocket launch site is located and $10 million to the City of Brownsville.
Musk has also flirted with more ambitious philanthropy goals. He tweeted last year that "if (the United Nations World Food Programme) can describe ... exactly how $6 billion will solve world hunger, I will sell Tesla stock right now and do it."
Musk was responding to a plea for a donation from David Beasley, the World Food Programme's executive director.
In January last year, he asked Twitter users about "ways to donate money that really make a difference (way harder than it seems.)"