Like I said, I don't get it. At least some of the reductions reformulate the problem so it can be attacked by some new tools. What's the point of reducing it to the efficient market hypothesis? That seems like an empirical claim rather than a mathematical one.
Ah, now I understand the motivation of your comment better. But I think if you read through just the introduction of the paper and consider that it was written in a finance journal and not a CS journal, showing the efficient market hypothesis to be NP-complete was ment to provide an insight into the efficient market hypothesis, not to provide any insight on the the P vs. NP problem.
