The billionaire philanthropist, who has long been the world's richest man, donated 64 million shares accounting for five percent 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 percent.
The recipient of the gift was not disclosed in the filing dated June 6. However, a SEC filing by the Bill & Melinda Gates Foundation on August 14, cited a donation by Microsoft of 64 million shares. The charity set up by Gates and his wife to promote global development has been the recipient of the majority of Gates' previous donations.
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.