Withholding easy-to-match exchanges is a common temptation in markets with middlemen. Think about the market for real estate. When the market is hot, easy-to-sell homes may never appear on the market at all. Instead, real estate brokers will match sellers who list with them and who aren’t asking too high a price with buyers who come to them for help buying a home and don’t need to sell their own home before they can buy one.
