It was business as usual on Goldman Sachs’s commodities-trading desk one Friday morning in December. With a steady thrum, dozens of men and women at rows of computer monitors on the fifth floor of Goldman’s headquarters in lower Manhattan bought and sold investments tied to oil, natural gas, power and metals.

"Clients still want the best price, and you still need to compete," said their boss, Gregory Agran, who went to work at Goldman in 1991 and then climbed the ladder to his current job as co-head of the commodities division.