Each year, China celebrates one of its most important holidays: Mid-Autumn Day.  It occurs in September, on the night of the full moon, and represents the beginning of the Fall.  Celebration includes, family gatherings, walks to look at the moon, and moon cake, a cake created just for that day, like fruit cake during the Western Christmas-Chanukah-New Year season.

Moon cake is a big part of the celebration, and stands at department stores begin to pop up several weeks before the day.  Another more subtle activity is moon cake arbitrage,  It begins with moon cake makers selling gift certificates to Chinese companies, many of which are government agencies or companies, who give them to employees.  Just about everyone in the country gets a moon cake from their work, it seems. 

The moon cake manufacturer sells the gift certificates, en masse, to a company for, say a 30% discount, on Y200 cakes.  Then, moon cake arbitrageurs stand around the vicinity of the ,moon cake stands and offer to buy the certificates for Y80.  And they sell them back to the company for Y120.

Thus, the arbitrageur makes a 50% return on his capital, and the moon cake company, who is effectively short moon cake certificates, covers its short at a return of about 20%.  Almost all of the parties, the original short seller, the moon cake maker, the receiver of the free gift certificate, and the moon cake arbitrageur, make money.  All funded by the companies who buy moon cake gift certificates for their employees.