Despite their big-brand names, the vast majority of Exxon, Chevron, BP and Shell gas statons are independently owned, so they aren’t able to make a volume play like wholesalers do. Although wholesalers are able to make a profit on gas, they’re not making much: Costco, for example, reported that gasoline has a lower profit margin than the rest of its business. Rising gas prices typically help Costco’s sales, but hurt its profits.