Enron and other energy suppliers earned profits by providing services such as wholesale trading and risk management in addition to building and maintaining electric power plants, natural gas pipelines, storage, and processing facilities. When accepting the risk of buying and selling products, merchants are allowed to report the selling price as revenues and the products' costs as cost of goods sold. In contrast, an "agent" provides a service to the customer, but does not take the same risks as merchants for buying and selling. Service providers, when classified as agents, may report trading and brokerage fees as revenue, although not for the full value of the transaction.