Wednesday, November 19, 2008

Tales from the Meltdown 3

An insightful interview with Bill Janeway on the theoretical underpinnings that enabled the meltdown:

It took two generations of the best and the brightest who were mathematically quick and decided to address themselves to the issues of capital markets. They made it possible to create the greatest mountain of leverage that the world has ever seen. In my own way, I do track it back to the construction of the architecture of modern finance theory, all the way back to Harry Markowitz writing a thesis at the University of Chicago which Milton Friedman didn’t think was economics. He was later convinced to allow Markowitz to get his doctorate at the University of Chicago in 1950. Then we go on through the evolution of modern finance and the work that led to the Nobel prizes, Miller, Modigliani, Scholes and Merton. The core of this grand project was to reconstruct financial economics as a branch of physics. If we could treat the agents, the atoms of the markets, people buying and selling, as if they were molecules, we could apply the same differential equations to finance that describe the behavior of molecules. What that entails is to take as the raw material, time series data, prices and returns, and look at them as the observables generated by processes which are stationary. By this I mean that the distribution of observables, the distribution of prices, is stable over time. So you can look at the statistical attributes like volatility and correlation amongst them, above all liquidity, as stable and mathematically describable. So consequently, you could construct ways to hedge any position by means of a “replicating portfolio” whose statistics would offset the securities you started with. There is a really important book written by a professor at the University of Edinburgh named Donald MacKenzie. He is a sociologist of economics and he went into the field, onto the floor in Chicago and the trading rooms, to do his research. He interviewed everybody and wrote a great book called An Engine Not a Camera. It is an analytical history of the evolution of modern finance theory. Where the title comes from is that modern finance theory was not a camera to capture how the markets worked, but rather an engine to transform them.

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