How are futures contracts prices correlated?
Given the convergence between spot prices and futures prices, would this indicate a positive or negative correlation?
Futures and spot prices differ at initiation because of interest rate, cost of storage, convenience yield etc. and converge at maturity because of the ‘no arbitrage’ principle. The futures price is however, calculated using the spot price (at initiation and afterwards) and therefore theoretically they should be significantly positively correlated assuming all else remains constant.
In reality, the strength of the correlation between the spot and futures is impacted by market forces and other factors. For example it has been found that some commodity futures price are strongly positively correlated to the spot when there is strong contango and less correlated (but positive) when there is backwardation. (Or weak contango)
You are asking a very interesting question. The answer depends on where the spot and futures price start at which means you have to look at the structure of the market- is it in contango or backwardation. Generally, if the market is in contango (futures price greater than spot), then the correlation would be negative, whereas if it was in backwardation (spot> futures), there would be a positive correlation. One caveat, I was exposed to this during the CFA curriculum, but very rarely use the knowledge, so my answer requires you to research it more thoroughly, but I hope it gives you an idea of what the question is dealing with.
Yale Bock, CFA
Y H& C Investments