According to a regulatory filing, Buffett on Wednesday donated another 2.4 million of the conglomerate's Class B shares, worth about $759 million based on their closing price.
Buffett donated 1.5 million shares to the Susan Thompson Buffett Foundation. Named for his late first wife, the foundation funds college scholarships to students from Nebraska, according to its website.
Another 900,000 shares were split evenly among charities run by his children Howard, Susan and Peter: the Howard G. Buffett Foundation, the Sherwood Foundation and the Novo Foundation.
Buffett has since 2006 donated more than half of his Berkshire shares, worth more than $46 billion at the time of the donations.
More than three-quarters have gone to the Gates Foundation, still one of the world's largest private charitable foundations despite last year's divorce of its namesake co-founders.
Berkshire and the Gates Foundation did not immediately respond to requests for comment.
Following the latest donations, Buffett still owns 15.5% of Berkshire's stock and controls 31.4% of its voting power.
Both percentages rise as the Omaha, Nebraska-based company repurchases its own shares from other investors.
Buffett is still worth $110.2 billion, ranking fifth worldwide, Forbes magazine said.
Berkshire owns dozens of businesses such as the BNSF railroad and Geico auto insurance, and stocks such as Apple Inc, Bank of America Corp and Occidental Petroleum Corp. Buffett has run the company since 1965.
According the Buffett family foundation websites, the Howard G. Buffett Foundation works to alleviate hunger, mitigate conflicts and improve public safety around the world. The Sherwood Foundation supports nonprofit organizations in Nebraska; the Novo Foundation aims to support communities,
(Reporting by Jonathan Stempel in New York)