Bill Gates on a return visit to the company he co-founded. (Microsoft Photo)

Bill Gates made a gift of 64 million Microsoft shares in June, according to a Securities and Exchange Commission filing made public on Monday. At a value of $4.6 billion, it’s his largest gift of Microsoft shares since 2000, representing about 38 percent of his remaining ownership of the company, according to Bloomberg News.

The recipient of this gigantic gift is unspecified in the regulatory filing, but if past practice holds, it’s likely the Bill & Melinda Gates Foundation, helping to fuel the philanthropy’s work in U.S. education and global health. We’ve contacted representatives of Gates, Microsoft and the Gates Foundation for more information.

[Update: A separate SEC filing by the Bill & Melinda Gates Foundation Trust on Monday showed a new holding of 64 million Microsoft shares, effectively confirming that this was a gift to the foundation. Thanks to Ben Silverman of InsiderScore for pointing this out after reading our story.]

With the stock gift, Gates’ personal Microsoft holdings have dipped below 2 percent for the first time, to about 1.3 percent, by Bloomberg’s calculations.

Gates typically sells Microsoft shares on a regular schedule, gradually whittling down his stake over the years. By comparison, he owned nearly a quarter of the company in 1996, a decade after Microsoft went public. In 2014, his stake dropped below 4 percent, making Steve Ballmer the company’s largest shareholder.

No longer working at the company day-to-day, Gates is still a Microsoft board member and technology adviser to CEO Satya Nadella, which Gates discussed with us earlier this year in the video below.

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