Warren Edward Buffett, born on August 30, 1930, in Omaha, Nebraska, is an American investor, businessman and philanthropist. Buffett, often called the "Oracle of Omaha", is regarded as one of the world's greatest stock market investors, and is the largest shareholder and CEO of Berkshire Hathaway. Buffett's philosophy on business investing is a modification of the value investing approach of his mentor Benjamin Graham. His investment style is also heavily influenced by Phil Fisher.