Blackstone President now among world's 500 richest people with $5.9 bn wealth

US-based Blackstone Group's President and Chief Operating Officer Jonathan Gray has joined the ranks of the world's 500 wealthiest people after a surge in the alternative-asset manager's shares. The net worth of the 51-year-old, who joined Blackstone in 1992, has jumped over 50% this year to $5.9 billion, according to Bloomberg Billionaires Index. He is the world's 495th richest person.