Bit of a sensationalist headline, but I was just wondering practically how you would position your portfolio to profit from a market downturn/crash.

Or to think about it in another way, what actually went up in the GFC when everyone found how correlated asset prices really were? And will it be different next time round?

There is the obvious answer of 100% cash but that would only be in a complete disaster scenario (when cash in the bank is unlikely to be that safe in any case) and I don't like that answer because of opportunity costs - the opportunities in the market for the long term are too unpredictable and too good to forego completely.

Possibilities as I see it include:

- deep out of the money put options over ASX 200 or All Ords. How could I find out profitability of such a play through the GFC - are there free option price histories out there?

- shorting particular stocks or a basket of stocks - but this is pretty limited by what the broker has available for shorting.

- index futures - but I have never used these before and am unfamiliar.

- installment warrants - XJO puts or can someone recommend something else?

- ETFs? For example the BEAR fund which is effectively an ETF short the index.

Any other creative medium term strategies for profiting in a downturn?