You operate a gas station.
You own a refined commodity. It turns over rapidly in your business. Every gallon you sell must be replaced by a new gallon or your customers go away. The commodity you own increases in value on world markets. Are you going to give yours away at the pre-increased prices knowing that you have to replace it at much higher prices or are you going to mark your inventory to market knowing quite well that you can sell it easily? If you sell it at the price you bought it for you have to replace it at much higher prices.
You aren't a fool. The gas you have is worth more than it was when you bought it but you still have to replace it and the cost has gone up.
Even worse, your gas sales have very little to do with your profit. You make your money from the convenience store. So you aren't an expert on gas or oil futures you just want to attract as much business as you can and you simply keep your prices competitive. But to keep customers coming you have to have gas to sell. THAT is what they stop for. So you have to have enough money in gas sales to replace the inventory. The gasoline on world markets goes to the highest bidder. You'd better get yours - so your company has a futures trader in the pits making sure you do.
How does he do it? He buys, even at higher prices, and you pass those prices on to your customer even though it isn't a big profit to you. You just want the traffic.
OIL IS A COMMODITY FOLKS. It isn't a car.
You fingured it out. Theses guy guys live on volume not on gross receipts.