Experimental double-auction commodity markets are known to exhibit robust convergence to competitive equilibria under stable or cyclical supply and demand conditions, but little is known about their performance in truly random environments. We provide a comprehensive study of double auctions in a stochastic setting where the equilibrium prices, trading volumes and gains from trade are highly variable across periods, and with commodity traders who may buy or sell their goods depending on market conditions and their individual outcomes. We find that performance in this stochastic environment is sensitive to underlying market conditions. Efficiency is higher and convergence to the competitive equilibrium stronger when the potential gains from trade are high and when the equilibrium spans a wide range of quantities, implying a large number of marginal trades. Speculative re-trading is prevalent, especially among those who have little to gain under equilibrium pricing. Those with the largest expected gains typically earn far less than predicted, while those with little or no predicted earnings gain modestly from speculation, leading to some redistribution of gains from high to low expected earners. Excessive trading volumes are associated with negative efficiencies in markets with low gains from trade, but not in the high-gains markets, where zero-sum trading and re-trading appear to enforce efficiency and near-equilibrium pricing. Buyers earn more relative to their competitive equilibrium benchmark than sellers do. Introducing trader specialization leads to fewer trading errors and higher market efficiency, but it does not eliminate zero-sum trading and re-trading.

已知实验性双拍卖商品市场在稳定或周期性的供需条件下表现出强劲的竞争均衡趋向，但对它们在真正随机环境中的表现了解甚少。我们对随机环境下的双重拍卖提供了全面的研究，在这种情况下，均衡价格，交易量和贸易收益在各个时期之间都存在很大差异，并且商品交易者可以根据市场条件和个人结果买卖商品。我们发现，在这种随机环境中的表现对潜在的市场状况敏感。当贸易的潜在收益很高并且均衡范围很广时，效率更高，对竞争均衡的收敛性也更高。意味着大量的边际交易。投机性重新交易很普遍，尤其是那些在均衡定价下几乎没有收益的交易。预期收益最大的人的收益通常远低于预期，而预期收益很少或没有的人由于投机而适度增长，导致收益从高预期者到低预期者的重新分配。交易量过大与贸易收益低的市场产生负效率有关，但高收益市场却没有，这与零和交易和重新交易似乎会提高效率和接近均衡的定价有关。与卖方的竞争均衡基准相比，买方的收入要高得多。引入交易者专业化可以减少交易错误并提高市场效率，