Warren Buffett is an American business magnate, investor, and philanthropist who is considered one of the most successful investors in the world. He formed Buffett Partnership Ltd. in 1956 which he used to acquire controlling stakes in companies like Berkshire Hathaway. Under his leadership, Berkshire Hathaway has become a large conglomerate holding company owning many businesses across diverse industries. Buffett is known for his value investing approach, buying whole companies, and philanthropic efforts.