Every stock market person knows what beta is.

It comes from a regression analysis, y = α + βx, where y is the return on a stock and x the return on the market).  It shows how a given stock’s past tendency to rise and fall is linked to fluctuations in the market in general.  A stock with a beta of 1.4, for example, has tended to rise and fall in the some direction as the market, but move 40% more in either direction; a stock with a beta of 0.8 has tended to exhibit only 80% of the market’s ups and downs.

The professor in a financial theory course I took in business school asked one day what it meant that gold stocks had, at the time, a beta of zero.

The thoughtless answer is that it means they aren’t risky, or that they don’t go up and down.

A consequence of this thinking is that you can lower the beta, and therefore the risk, of your investment portfolio by mixing in some gold stocks.What’s interesting is that in the early days of beta analysis that’s what some institutional portfolio managers actually did with their clients’ money.

That didn’t work out well at all.

What should have been obvious, but wasn’t, is that the zero beta didn’t mean no risk–or that gold stocks are/were a good investment.  It meant what the regression literally indicates–that none of the movement in gold stocks could be explained by movements in the stock market in general.

The riskiness of gold stocks is there, but it came/comes in other dimensions, like:  how mines develop new supply, the ruminations of the gnomes of Zürich (in today’s world, Mumbai and Shanghai), the potential for emerging country craziness, the propensity of the industry to fraud.

Why write about this now?

I heard a Bloomberg report that institutional investors as a whole are upping their exposure to hedge funds, despite the wretched performance of the asset class.  Their rationale?   …uncorrelated returns.

It sounds sooo familiar.

Admittedly, there may be a deeper game in progress.  It’s impossible to say your plan is fully funded by projecting a gazillion percent return on stocks or bonds.  But who’s to say that a hedge fund can’t do that?