Buffett donates $3.4 billion to Gates' and family charities

(Reuters) - Warren Buffett has donated roughly $3.4 billion of Berkshire Hathaway Inc stock to five charities, the billionaire's largest contribution in his plan to give away his fortune.

Buffett's 13th annual donation comprised about 17.7 million Class "B" shares of Berkshire, valued at $192 each as of Monday's market close.

The largest block went to the Bill & Melinda Gates Foundation. Buffett's own foundation, named for his late first wife Susan, and charities run by his children Howard, Susan and Peter received the rest.

(Reporting by Jonathan Stempel in New York; Editing by Susan Thomas)