Such trades are assumed to have played a key stage in our own evolution towards Homo economicus. Previous studies involved training chimps to trade tokens for food - a less realistic model, given that apes tend not to carry round purses of tokens in the wild.
The researchers found that chimps do not spontaneously trade their food, but can be trained to do so. With training, they're willing to swap a less-liked food such as carrots for tastier fruit, but remained reluctant to engage in near-comparable trades such as apples for grapes. Lead author Mark Grady of UCLA’s Center for Law and Economics reckons this reflects the lack of ownership rights among our primate cousins.
Still, this must raise the possibility that apes could be trained to take over some roles in the mainstream markets. There might be initial problems with all the screeching, scratching and fighting for alpha-male dominance, but I'm sure the chimps could get used to it.
And, bearing in mind the old theorem about monkeys writing Shakespeare, how many chimps on how many trading desks would it take to fuck up as spectacularly as some human traders?