The world’s richest man sold 5,044,000 Tesla shares between Nov. 19 and Nov. 29, and it was given to charity, according to the SEC.

Where in the world did Elon Musk donate that $6 billion?

On Monday, the Wall Street Journal reported that the Tesla CEO gave around $5.74 billion to charity during a mass share-selling spree in November. Musk, 50, sold 5,044,000 Tesla shares—which was then trading at above $1,060—between Nov. 19 and Nov. 29, and the money was given to charity, according to an SEC filing.

Although it was one of the largest donations to charity ever recorded, details about where the money went remain unclear. The SEC filing reveals no information about a potential recipient, and Musk has remained tight-lipped about who received the donation.

We do know that Musk has offloaded $16.4 billion worth of shares—or 10 percent of his total stake in Tesla—since November. In a recent interview, he said it was to cover taxes exercised on expiring options next year. But the timing of the recent donation mysteriously coincides with an interaction between Musk and one foundation, which could hint at its ultimate landing place. Or not.

Back in late October, David Beasley, the director of the World Food Programme, called on the world’s billionaires— specifically mentioning Musk and Jeff Bezos—to step up and donate a small fraction of their net worth to help solve world hunger. In an interview with CNN, Beasley said that all that was needed was “$6 billion to help 42 million people that are literally going to die if we don’t reach them. It’s not complicated.”