How a couple of 'dirty-style' wall murals came to be worth $200m

David Choe’s mural in Facebook’s California office. He was paid in shares for his work - a good decision now that his stake is potentially worth $200m

Damien Hirst may lose his record for selling the most expensive piece of art ever – and not to another enfant terrible of the art world either, but to a Los Angeles mural painter who happened upon the Facebook offices in 2005.

David Choe could be the unlikeliest of all the millionaires and billionaires who will be minted by the social network's flotation this spring. If the company hits the top valuations being talked about, then Mr Choe will have been paid about $200m (£126m) for the "graphic sexual murals" that adorned Facebook's walls in its early years.

Mr Choe, who says his "dirty-style figure paintings combine themes of desire, degradation, and exaltation", took shares in Facebook instead of a cash payment. He told friends at the time that Facebook was a "ridiculous and pointless" idea that wouldn't succeed, but he made the gamble, and now the shares look like being the hottest property on the US stock market.

With Facebook being pitched in the $75bn-$100bn range, those murals could turn out to be more expensive than the $200.7m Hirst raised at auction in 2008 for his collection of preserved animal corpses, diamond-encrusted skulls, and paintings with rosaries, crucifixes and cigarette butts.

Although Mr Choe declined to speak about his new-found wealth when the New York Times tracked him down, his Facebook fanpage tells his story: "In 2005, internet entrepreneur Sean Parker, a longtime fan, asked him to paint graphic sexual murals in the interior of Facebook's first Silicon Valley office, and in 2007, Facebook chief executive Mark Zuckerberg commissioned him to paint somewhat tamer murals for their next office."

Mr Parker, the founder of Napster, was on the Facebook board in 2005 and joins the ranks of Facebook billionaires. He was played by Justin Timberlake in the movie of the company's early days, The Social Network, in which he is reputed to have said: "A million dollars isn't cool. You know what's cool? One billion dollars."

About 250 of Facebook's earliest employees, many still at the company, will be worth millions of dollars on paper after the flotation, thanks to share options handed out after it was created by Mr Zuckerberg.