The richest people on Earth got richer in 2014, adding $92 billion to their collective fortune in the face of falling energy prices and geopolitical turmoil.

The net worth of the world's 400 wealthiest billionaires on Monday stood at $4.1 trillion, according to the Bloomberg Billionaires Index, a daily ranking of the world's richest.

The biggest gainer was Jack Ma, the co-founder of Alibaba Group Holding Ltd, China's biggest e-commerce company. Ma, a former English teacher who started the Hangzhou-based company in his apartment in 1999, added $25.1 billion to his fortune, riding a 56 percent surge in the company's shares since its September initial public offering. Ma, 50, briefly passed Li Ka-shing as Asia's richest person.