The Omaha, Neb., billionaire investor donated 18,628,189 Class B shares in Berkshire Hathaway to five foundations: the Bill & Melinda Gates Foundation, Susan Thompson Buffett Foundation, Sherwood Foundation, Howard G. Buffett Foundation and NoVo Foundation. In order to make the contributions, Mr. Buffett converted his A shares in Berkshire Hathaway to Class B shares. Last year, Mr. Buffett made donations totaling $2.86 billion to charities. Mr. Buffett, 86, is Berkshire's largest shareholder and as of March held 32.7% of the voting power in the conglomerate. Mr.