inefficiencies, such as under- and overtreatment or market break-down. We study in a large experiment with 936 participants the … has little influence, as predicted. Seller competition drives down prices and yields maximal trade, but does not lead to …

, verifiability fails to yield efficiency in experiments with endogenous prices. We identify heterogeneous distributional preferences … as the main cause and design a parsimonious experiment with exogenous prices that allows classifying experts as either …-standard distributional preferences, among which efficiency-loving and inequality aversion are most frequent. We discuss implications for …