The business model of a trading firm

A commodity trading firm makes money by exploiting differences — not by guessing the direction of price. There are three classic forms of arbitrage, and almost every real trade is a mix of them.

1. 1Space (geographical): the same commodity is cheaper where it's produced than where it's needed. The trader captures the gap by moving it — and pays for freight, insurance and risk out of that gap.
2. 2Time (temporal): a commodity is cheap now and worth more later (e.g., a harvest glut vs. winter demand). The trader stores it and captures the spread — paying storage and financing in the meantime.
3. 3Form (transformation): raw material is worth more after blending, processing, or splitting into grades. The trader buys the input, transforms it, and sells the more valuable output.

Where the margin really comes from

In each case the firm is paid for a service: logistics, financing, risk-bearing, market access, quality transformation. The flat price of the commodity is usually hedged away (you'll see how in the Risk module) so the firm is left earning the spread for the service it provides, not a bet on whether oil goes up or down.

This is why large houses look like logistics and finance companies with a trading desk attached. They own or charter ships, lease tanks and warehouses, run inspection and blending operations, and have huge credit lines from banks. Scale lets them move more volume at thin margins; specialists win by finding niches the giants ignore.