New Delhi, July 25 -- Warren Buffett, who started giving away his wealth two decades ago, has pledged to completely dispose of his roughly $140 billion stake in Berkshire Hathaway Inc. by 2034.

His latest donation, comprising 12 million Class B shares, is instead going to four foundations led by his children, Susie, Howard and Peter. Noting that his children were getting older and were ready to distribute his wealth, Buffett said in interview excerpts on CNBC, "I tell the three children that it is theirs, and it's their responsibility to get it done well."

While some applauded his decision to direct wealth to charitable causes, others questioned whether foundations were the best vehicle for supporting vulnerable Americans. And some accu...