"When you place an order to buy or sell a stock, your broker has choices on where to execute your order. Instead of routing your order to a market or market-makers for execution, your broker may fill the order from the firm's own inventory – this is called 'internalization'. In this way, your broker's firm may make money on the "spread" – which is the difference between the purchase price and the sale price."[7] For a related issue regarding trade execution, see payment for order flow.