Part of the manipulation is the market place. If they produce too much product and can not sell it they lower the price to reduce inventory. Oil in the ground is a fixed inventory which can be manipulated by say someone like Obama closing much land to production. News stories can cause panic and even boycott of product manipulating the market. The main ruler of the market is the dollar so there are thousands of schemes to manipulate products to get more dollars. Dollars and greedy
rule the market.
You have a good day then.
Cheers!