Mark Zuckerberg lost $31 billion in wealth since record in July

American social networking giant Facebook's Co-Founder and CEO Mark Zuckerberg's fortune has fallen more than $31 billion from its peak on July 25. The 34-year-old who recently was the world's third-richest person is now ranked sixth on the Bloomberg Billionaires Index with a net worth of $55.3 billion. So far this year, Zuckerberg has lost $17.4 billion.