We propose a formal model for trading of complex goods, and present an automated exchange for a limited version of this model. The exchange allows the traders to describe commodities by multiple attributes; for example, a car buyer may specify a model, options, color, and other desirable properties. Furthermore, a trader may enter constraints on the acceptable items rather than a specific item; for example, a buyer may look for any car that satisfies certain constraints, rather than for one particular vehicle.
We present an extensive empirical evaluation of the implemented exchange, using artificial data, and then give results for two real-world markets, used cars and commercial paper. The experiments show that the system supports markets with up to 260,000 orders, and generates one hundred to one thousand trades per second.