The fortune of the Facebook founder yesterday rose by $5.5-billion in early stock market trading as the world's biggest social network delivered another quarter of record revenue.

That gives the 31-year-old a net worth of about $47-billion, enough to surpass the $45.3-billion holdings of brothers Charles and David Koch.

Facebook reported on Wednesday that fourth-quarter sales were up 52% to $5.84-billion and net income had more than doubled to $1.56-billion from a year earlier.

Yesterday's surge turned a year-to-date decline of more than $4-billion for Zuckerberg into a $1.2-billion gain for the year and pushed him above the Kochs, whose businesses have been hit by lower oil prices.

The five billionaires above Zuckerberg in the ranking - Bill Gates, Amancio Ortega, Warren Buffett, Jeff Bezos and Carlos Slim - have lost a combined $24-billion as global equities slumped amid dimming investor expectations of global growth.