Bill Gates has made his largest donation in 17 years, giving away $4.6 billion (S$6.28 billion) worth of shares in Microsoft Corp.
The billionaire philanthropist, who has long been the world's richest man, donated 64 million shares accounting for five per cent of his overall fortune, according to a Securities & Exchange Commission filing released Monday and first cited by Bloomberg.
The donation reduces Gates stake in the software maker to 1.3 per cent.
The recipient of the gift was not disclosed in the filing dated June 6, though the majority of his prior donations have been to the Bill & Melinda Gates Foundation, the charity set up by Gates and his wife to promote global development.
Gates' most recent pledge takes his overall charitable donations to approximately $50 billion, based on the foundation's most recent financial statement.
In 2000, the businessman who co-founded Microsoft in 1975, gave away more than $20 billion worth of shares, according to Bloomberg calculations.
Gates' estimated net worth is $89.9 billion, as of July 2017. He was briefly overtaken by Amazon founder Jeff Bezos as the world's richest man on 27 July this year.