[marvin]

There are probably lots of loopholes, but we don't know about them. It can't be a coincidence that the largest hedge funds have beaten the market spectacularly every year the last 20 years. (And if they put 10% some of those gains in a money market account, they are guaranteed to have made positive returns no matter what happens).

My personal this-is-what-i-think theory is that there are lots of patterns in the pricing of equities and other market components, but if they ever become publicly known, they cease to exist. The best hedge funds (or best traders, take your pick) manage to find patterns that no one else does. This does not protect them from a spectacular implosion if their models for some reason become invalid.

There is a cult of believing in the perfect randomness of market pricing. Saying that market developments are random is practically the same as believing in the efficient market hypothesis. The market cannot be perfectly efficient, because there are always interactions that no one will be able to predict. Most of these interactions are no doubt chaotic (unpredictable), but there is no way that traders instantly discover every pattern that is predictable.