NEW YORK – Facebook CEO Mark Zuckerberg officially is now the sixth richest person in the world and the fourth richest in the United States.

The Facebook Inc founder saw his fortune rise $6 billion in trading on Thursday after the world’s biggest social network delivered another quarter of record revenue.

The teenager who started his empire from a Harvard dorm room and successfully launched the most popular social network in the world outdid oil tycoons Charles and David Koch, aged 80 and 75 respectively, in terms of wealth this week, according to the Bloomberg Billionaires Index.

Facebook Inc shares surged 15.5 per cent on Thursday, their biggest percentage increase since July 2013, after the social networking service posted quarterly results that blew away expectations on every key measure.

Facebook shares closed at $109.11 putting its market capitalization at about $308.6 billion. That would make it the fourth most valuable technology company, overtaking Amazon.com Inc, which was valued at about $296 billion ahead of its results on Thursday. Facebook said it had 1.59 billion monthly active users as of December 31, about one in every four people in the world.

Bill Gates, Amancio Ortega and Warren Buffet continue to hold their places as the three richest men in the world, with Gates at number one.

Last month, with the birth of his first child, Zuckerberg promised to donate most of his fortune to the Chan Zuckerberg Initiative, a company set up by himself and his wife, Priscilla Chan. The initiative will lobby for political change, fund philanthropic causes and invest in companies.