commodities, which already have a market price Balls. Go to a commodity exchange and you know how you find the price? The last price paid at auction. Sometime

commodities, which already have a market price Balls. Go to a commodity exchange and you know how you find the price? The last price paid at auction. Sometimes the negotiation is disguised, using an order book or dealer system. But sometimes they even explicitly run a call auction. All Wall Street is is a continuous auction house. All Supply/Demand is is a continuous auction.