Twilight of the Quants (or yet another reason for the current financial turmoil)
The most recent Buttonwood column in The Economist (25 Oct. 2007), sheds light on how 'quants' have been adding risk to the market because of their strategies. These quant funds are staffed by mathematicians, physicists, etc., that are suppose to come up with ultra-sophisticated models that should, they promise, lead to higher returns. But the problem is that other funds also hire quants that use similar models. This leads to a kind of feeding frenzy (or a vicious cycle) where an increasing number of very smart people are chasing ever shrinking opportunities for genuine arbitrage profits, which causes them to either ratchet up risks and/or try ever more esoteric strategies (which are copied almost as soon as there is any profit to be made), which, in turn, lead them further down the slippery slope.
For that reason, as well as others, these funds -- just as recently foreclosed home owners and their subprime mortgage lenders (who, presumably, didn't do PhDs in maths, physics, or engineering) -- loaded up on leverage (either directly or indirectly via derivatives, etc.). When the markets turned against the quants, they tried to offload their now toxic investments (in credit derivatives, etc.). Of course they couldn't find buyers, so they had to unload more liquid and valuable investments in order to meet margin calls and/or stay in business. But all this did was to cause a stampede among quant funds to get rid of assets that they really shouldn't have gotten rid of but HAD TO because of margin calls, the need to delta hedge their positions, plain desperation, etc.
This is the story of so many financial bubbles bursting -- except on a high tech, post-modern level. This, according to Buttonwood, is what happened during August. It seems that no one on Wall Street or in the City has a memory beyond their last bonus. Didn't we go through this with LTCM? Program trading in October 1987? Yet we are told that ever more sophisticated models or ever faster execution of orders will lead to greater returns. But what these 'geniuses' don't realize is that the world doesn't always fit their 'sophisticated' models. Common sense should have told them that strategies and assets that weren't correlated before will become correlated once everyone else with a PhD in Computational Chemistry decides to sell similar things at the same time! The rules of the game are the same whether you are a down-on-your-luck homeowner or an over-educated quant.
But to be fair, quants shouldn't shoulder all the blame. Yes, it's true that, as the article points out, "instead of providing liquidity in a crisis, the quants added to the instability." But the same could be said for those who participated in the dotcom bubble, tulip-mania, the Roaring 20s, and a whole host of financial fads and fashions that went awry. The problem is not that we are too sophisticated or that we are not sophisticated enough; the problem is arrogance. The problem is being willfully blind to 'Black Swans.' I doubt that any amount of rigorous modelling, algorithmic trading, statistical arbitrage, or improvements in order executions will solve that problem.