As it approaches a public offering, how Glencore—founded by the legendary fugitive March Rich—cornered the market for just about everything by working with dictators and spies.

Who simultaneously did business with the U.S. government, the besieged Syrian regime, and the Libyan rebels last month? The group of 16 trading houses that collectively are “worth over a trillion dollars in annual revenue and control more than half the world’s freely traded commodities.”