Rakesh Jhunjhunwala, after battling health problems for a while, passed away in August last year. According to Forbes, the billionaire had amassed a fortune worth an estimated $5.8 billion. As a young investor, Jhunjhunwala found a mentor in Radhakishan Damani at a time when the stock market index Sensex was at 150; it now trades at over 61,000.