I'm trying to get a handle on who has the most significant impact on price over the numbererous futures and spot markets. Obviously it will depend on the contract in question (and obviously there is arbitrage to bring the spot and futures into line).

But lets take gold and copper for examples.

Who would be taking the 'lead' in setting price?

Would it be commex futures? or lme spot prices? or lme futures?

or are they equally significant and arbitraged accordingly?