Can he reach $100 billion? Probably yes. 

According to the real-time rankings from Bloomberg's Billionaire Index, Bill Gates' net worth has now crossed the $90 billion value.

Gates' net worth did not climb because of any stock rise at Microsoft, but because of jumps in the shares of Canadian National Railway (CNI) Company and Ecolab (ECL), two smaller companies in which he has holdings.

He's well ahead of Amancio Ortega, the Spanish retailer who is the world's second richest man with a fortune of $76 billion.

Facebook founder and CEO Mark Zuckerberg has enjoyed an $8.9 billion jump in his net worth, while Harold Hamm, CEO of shale oil producer Continental Resources (CLR), has seen his net worth more than double. Hamm's fortune gained $7 billion, lifting his net worth to $13 billion.

Amazon (AMZN, Tech30) CEO Jeff Bezos' net worth rose $6.5 billion this year. He is now virtually tied with Warren Buffett for third place on the ranking of world's richest men.