White, a 23-year-old from California, won the gold medal in the half-pipe at the last Winter Olympics in Turin and has since earned a string of personal endorsement deals with the likes of snowboard-maker Burton, Red Bull, Target, goggle-maker Oakley, game-maker Ubisoft and AT&T.

Red Bull even built him his own $500,000 (£318,250) half-pipe in Silverton, Colorado, which is so remote he needs a helicopter to shuttle him there so he can practice his signature trick, double McTwist 1260, an inverted aerial in which he launches himself up off the side of a snow packed embankment and flips head over heels twice while spinning three-and-a-half times and holding his board.

Kim won a number of major titles last year, including the World Championship, Grand Prix Final Champion and Four Continents Champion, earning her $150,000 (£95,475) in prize money.

But, like White, she earns the majority of her money in sponsorship deals, including with Samsung, who last May launched the Yu-Na Haptic style phone which sold more than a million in just seven months, a record for the company.

Kim also has sponsorship deals with Hyundai Motors, Kookim Bank, Nike and Proctor & Gamble.

Forbes wrote: "In terms of earning potential, White and Yu-Na are typical Olympic athletes.

"They are dependent on sponsors, rather than competition prize money, to make a living in their sport.

"But the recent economic downturn has made it harder to turn gold medals into cash.

"Already at a disadvantage compared to most of their Summer Olympic siblings whose sports are more popular and marketable (think swimming's Michael Phelps or gymnastics' Mary Lou Retton), many Winter Olympian hopefuls have struggled with the loss of sponsors leading to the 2010 Vancouver Games."

The third highest-earning athlete on Forbes' list, which excludes professional NHL ice hockey players, was American skier Lindsey Vonn, who thanks to deals with Red Bull, UnderArmour, Proctor & Gamble and recent addition Rolex, Vonn earned $2.5 million (£1.5 million) last year and another $350,000 (£223,000) in prize money last year.

Other notable names on the list include short track speed skater Apolo Anton Ohno, a two-time Olympic gold medallist, and skier Bode Miller, a two-time Olympic silver medallist in Salt Lake City eight years ago, who Forbes estimate both earned $1.5 million (£955,000) and $1.3 million (£827,000) respectively last year.

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