The world’s 400 richest people lost $182 billion this week from their collective fortunes as weak manufacturing data from China and a rout in commodities sent global markets plunging, Bloomberg reported.

The weekly drop for the Bloomberg Billionaires Index, a group that includes Warren Buffett and Glencore Plc’s Ivan Glasenberg, was the biggest since tracking of the expanded list began in September 2014.

The combined net worth of the index members fell by $76 billion on Friday alone, when the Standard & Poor’s 500 Index of US stocks ended its worst week since 2011.

Friday’s losses put the world’s richest 400 into the red for the year to date. They’re now down $74 billion in 2015, with a collective net worth of $3.98 trillion.

The week’s largest setback in dollar terms was experienced by Buffett, who saw his fortune drop by $3.6 billion as Berkshire Hathaway Inc. slipped more than 5 percent.

The investor is the world’s third-wealthiest person, with a fortune of $63.4 billion, according to data compiled by Bloomberg.