Warren Buffett of Berkshire Hathaway placed third while the founder of Zara, Amancio Ortega of Spain, slipped down a position from last year to number four.
America's Evan Spiegel, co-founder of photo messaging app Snapchat, became the youngest billionaire this year at the age of 24.
A record number of 290 people joined the list for the first time, of whom 25% hail from China, which produced a world-leading 71 newcomers.
Self-made billionaires made up the largest number of people on the list with 1,191 positions while just 230 came into their wealth through inheritance.
Iceland again has a billionaire in the list after a gap of five years with the entry of Björgólfur Thor Björgólfsson.