(Adds details of donations, prior donations, byline)
By Jonathan Stempel
July 16 (Reuters) - Warren Buffett has donated roughly $3.4 billion of Berkshire Hathaway Inc stock to five charities, the billionaire's largest contribution in his longstanding 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.
Buffett, 87, has since 2006 made more than $30.9 billion in donations to the charities, including roughly $24.5 billion to the Gates Foundation.
His largest previous annual donation had been $3.17 billion, in 2017.
Buffett still owns roughly one-sixth of Berkshire, the Omaha, Nebraska-based conglomerate he has run since 1965, despite giving away 43 percent of the shares he owned in 2006.
Following the latest donation, Buffett was expected to rank as the world's fourth-richest person, worth $79.2 billion, according to Forbes magazine.
He would have trailed Amazon.com Inc founder Jeff Bezos' $149.7 billion, Microsoft Corp co-founder Bill Gates' $93.6 billion, and LVMH Moet Hennessy Louis Vuitton Chief Executive Bernard Arnault's $80 billion.
Facebook Inc co-founder and Chief Executive Mark Zuckerberg ranked fifth, at $78.5 billion.
The five charities typically sell Buffett's shares to finance their activities, reflecting his desire that money be spent. Buffett makes smaller donations to other charities. (Reporting by Jonathan Stempel in New York; Editing by Susan Thomas and Diane Craft)