Warren Buffett is the CEO of the Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B) holding company, where he oversees a $281 billion portfolio of publicly traded stocks and securities, in addition to several privately held subsidiaries. Berkshire is also sitting on a record $334 billion in cash, which Buffett and his team can deploy when they spot new opportunities. Had you invested $1,000 in Berkshire stock when Buffett took the helm in 1965, it would be worth an eye-popping $44.7 million today.