Bill Gates has given away $4.6bn to charity in his largest donation since 2000.
The 64 million shares are equivalent to 5% of his total fortune, currently estimated to be $89.9bn.
Since 1994 Mr Gates, 61, and his wife Melinda have given away a total of $35bn in cash and stocks to a range of charitable causes.
The donation was made in June but became public on Monday following the filing of a document with the US Securities and Exchange Commission.
Mr Gates’ share in Microsoft is now just 1.3%. Prior to this, Mr Gates gave away $16bn in Microsoft shares in 1999 and $5.1bn in 2000.
The majority of all previous donations have been made to the Bill & Melinda Gates Foundation, which is primarily focused on reducing world poverty, combating infectious diseases and providing universal access to computers.
It is not known who the recipient of this latest donation is at this time.
