Warren Buffett donates $5.3b Berkshire Hathaway stock

Warren Buffett has donated another $5.3 billion of Berkshire Hathaway stock to the Bill & Melinda Gates Foundation and four family charities, his biggest annual donation since he began making them in 2006.

Buffett's donation boosted his overall giving to the charities to about $57 billion, including to the family charities in the last two Novembers.

The latest donation included about 13 million Berkshire Class B shares.

Buffett donated 9.93 million shares to the Gates Foundation, and has donated more than $43 billion of Berkshire shares there overall.

He also donated 993,035 shares to the Susan Thompson Buffett Foundation, named for his late first wife, and 695,122 shares to each of three charities led by his children Howard, Susan and Peter: the Howard G. Buffett Foundation, the Sherwood Foundation and the NoVo Foundation.

Buffett, 93, plans to give away more than 99 per cent of the fortune he built at Omaha, Nebraska-based Berkshire, which he has run since 1965, with his children serving as executors of his will.

Berkshire is an approximately $880 billion conglomerate that owns dozens of businesses including the BNSF railroad and Geico car insurance, and stocks such as Apple.

Buffett still owns 14.5 per cent of Berkshire's outstanding shares, a Friday regulatory filing shows, despite having given away more than half of his stock since 2006.

His $128.4 billion fortune makes him the world's 10th-richest person, according to Forbes magazine.