The Colombian-born vendor ordered an extra shipment of canary-colored panties, thongs, boy shorts, bikinis and briefs. He only has a few pairs left. He's already sold out of the g-strings twice.

"Most of the year I can't sell one pair of [yellow] underwear," says Varon, pointing to the few that remain on the rack. "But when it starts getting close to the New Year, I can't keep them in the store."

Why are yellow undies so red hot?

In many Spanish-speaking countries, wearing yellow panties into the New Year will bring wealth and luck. Yellow is the color of choice because it is most closely associated with gold, Varon says.

"With the economy the way it is, I'm sure a lot of women will be wearing yellow this year," he says.

Tradition says you must cast away your old underwear at the stroke of midnight on New Year's and put on a yellow pair. To be lucky, they must be new. Want some extra luck? Wear them inside out. How you get the underwear is believed to make a difference, too; receiving them as a gift is said to be best.