In capitalism, Marx argues, commodity values are commercially expressed as the prices of production of commodities (cost-price + average profit). Prices of production are established jointly by average input costs "and" by the ruling profit margins applying to outputs sold. They reflect the fact that production has become totally integrated into the circuits of commodity trade, in which capital accumulation becomes the dominant motive. But what prices of production simultaneously hide is the social nature of the valorisation process, i.e. how an increase in capital-value occurs through production.