In my reply to this, I should have been more explicit. When you have two or more instruments that you are not sure what their connection is, the right tool to use is something like a VAR model.@nitro I assume when you say logical you mean fundamental? i.e. the assets are bound by some fundamental reason.
It is interesting that you avoid equities, I don't exclude any particular asset classes. I base selections on fundamental reasons, for example, assets that share a common underlying bias where that underlying may be a commodity, interest rate, or semiconductor prices, etc.
I take a bunch of assets with a fundamental bias and rank them according to strength of reversion at various time frames. The beauty of this game is there are literally an unlimited number of markets you can create. I'm a professional software developer and use my own software models to do this. I trade small and use pdf to ensure the odds are skewed in my favour.
The next trick is to expand the selections and utilise assets with varying currencies, do you do this?
I'm not sure of the best way to do this, should I convert the prices 'on-the-fly' to a common currency, or should I hedge the currency risk for the individual legs ?
When you have two or more instruments where you are pretty certain there is a fundamental tie between them, then it is more useful to use a VEC model.
Notice that thinking about both of those it is useful to think of them under a more general category of Factor Models.
That answer I think is more useful than the one I gave.
