The Chinese stock market dropped 8.5 percent Monday, the biggest single-day decline since 2007, and the world's 400 richest people lost about $124 billion collectively.Chinese billionaire Wang Jianlin suffered the most severe losses of any billionaire worldwide, according to the Bloomberg Billionaires Index, after Chinese stocks slid dramatically on Black Monday. Wang saw his fortune decline after both his companies—Dalian Wanda Commercial Properties Co. and Wanda Cinema Line Co.—plunged 17 per cent and 10 per cent, respectively. 

China's second richest person Jack Ma, founder of e-commerce giant Alibaba, lost “only” $545 million on Monday, according to the index.

China's decision of cutting down its currency (Yuan) rate is major reason for sink of world stocks. Twenty-four billionaires saw their wealth fall by more than $1 billion on Monday. They included Bill Gates, whose wealth dropped $3.2 billion; the most of anyone after Wang, and Inditex SA founder Amancio Ortega, whose wealth fell $1.5 billion

Indian billionaires recorded falls equivalent to 6.6 percent of their overall wealth. India's second richest person Mukesh Ambani lost $1.8 billion, or 9.2 percent of his net worth. 

One Japanese billionaire, meanwhile, even benefited from the chaos. Tadashi Yanai, the richest person in Japan, gained $106 million as the yen strengthened against the dollar.