Berkshire Hathaway Inc. is an American multinational conglomerate holding company headquartered in Omaha, Nebraska, United States. Founded in 1839 as a textile manufacturer, it underwent a drastic restructuring into a conglomerate starting in 1965 under the leadership of chairman and CEO Warren Buffett and vice chairman Charlie Munger. The company's main business and source of capital is insurance, from which it invests the float in a broad portfolio of subsidiaries, equity positions and other securities. Buffett and Munger are known for their advocacy of value investing principles and under their direction, the company's book value has grown at an average rate of 20%, compared to about 10% from the S&P 500 index with dividends included over the same period, while employing large amounts of capital and minimal debt.