Asset Pricing and Risk Sharing in Complete Markets: An Experimental Investigation

Abstract

We study asset pricing and risk sharing in experimental financial markets designed to test rational choice and competitive behavior in complete markets. We find that participants behave competitively but deviate from rationality: approximately 25% of their actions are first-order stochastically dominated. To interpret these experimental findings, we propose a random-choice model predicting that market-clearing prices and average trades should converge to those in the rational-choice competitive equilibrium as market size grows. Our experimental data support this convergence prediction. A structural estimation under CRRA utilities and logit choice probabilities reveals that approximately 20% of participants would have obtained higher expected utility in autarky, suggesting that bounded rationality can make market participation welfare-reducing for a significant minority.

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Reference

Bruno Biais, Thomas Mariotti, Sophie Moinas, and Sébastien Pouget, “Asset Pricing and Risk Sharing in Complete Markets: An Experimental Investigation”, TSE Working Paper, n. 17-798, April 2017, revised March 2026.