Warren Buffett has donated another $US1.78 billion to several charities, with most going to the Bill and Melinda Gates Foundation.
The billionaire US investor has given the charity run by the co-founder of Microsoft 23.31 million shares in his investment company Berkshire Hathaway.
The BBC reports the shares were passed to the foundation on Wednesday, when they closed trading at $US76.52.
Mr Buffett, 80, plans to give away 99% of his wealth. He first announced this in 2006. This week's donation is his sixth since then.
Other shares transferred on Wednesday went to four charities run by his family.
Mr Buffet has now donated more than $US11 billion of shares in Berkshire Hathaway.
He is the world's third-richest person, worth an estimated $US50 billion.