Wholesale trade margins, or markups, reflect the value added by wholesalers in the distribution of a product from producers to purchasers. Wholesale trade output is margin based (sales less the costs of goods sold) instead of purely sales based, meaning wholesale trade values reflect margins received and do not necessarily reflect trends in sales. Wholesale trade in the space economy reflects margins earned on the use of space-related products as intermediate inputs (such as GPS receivers in cell phones) and in the distribution of final products (such as satellite phones).