Randomized double auctions: gains from trade,trader roles,and price discovery

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.

     

Concurrent trading in two experimental markets with demand interdependence

Summary. We report results from fifteen computerized double auctions with concurrent trading of two commodities. In contrast to prior experimental markets, buyers' demands are induced via CES earnings functions defined over the two traded goods, with a fiat money expenditure constraint. Sellers receive independent marginal cost arrays for each commodity. Parameters for buyers' earnings functions and sellers' costs are set to yield a stable, competitive equilibrium. In spite of the complexity introduced by the demand interdependence, the competitive model is a good predictor of market outcomes, although prices tend to be above (below) the competitive prediction in the low-price (high-price) market.     

零售业态的生成与演进：基于知识的分析

零售业态的车轮理论是以竞争优势和技术的外生论为基础的。把企业的知识理论运用于零售企业及业态的分析可以发现：零售知识螺旋是业态生成的微观基础；零售业态螺旋是业态演进的路径特征。与车轮理论相比，螺旋理论兼顾了业态运行中的竞争与合作、成本与收益，并揭示了业态竞争优势的源泉，因而对我国零售业态变迁具有较强的解释力。     

市场结构及市场效率的实验经济学综述

实验经济学对于市场效率和市场结构的研究最早在1948年由Chamberline开创。经济学家经过大量实验发现,不但市场前提假设关系到市场均衡结果及效率,交易制度也会对均衡产生重大影响。并且,不符合完全竞争市场假设的市场结构也有可能实现资源有效配置。本文对实验经济学关于市场结构及市场效率的相关研究进行了回顾与综述,并重点阐述其对完全竞争市场的研究,以揭示交易制度及市场前提对市场效率的综合影响。本文得到的结论显示：即使没有达到完全竞争市场的严格假设,也可能达到完全竞争市场的均衡状态,因而达到最优的配置效率。并且,对于市场结构——完全竞争、垄断和寡头垄断市场的实验研究也表明,并不是如传统古典经济学模型所言：只有完全竞争的市场结构才能够达到资源的有效配置,垄断市场效率也并不是完全与模型所言一致。而且不同于古典经济学,实验经济学将交易制度看作外生变量,认为其对最终市场效率也会产生很大影响。     

Value theory with personalized trading

This paper extends existing general equilibrium theory to describe the competitive production and allocation of “personalized commodities:” commodities with only one potential buyer or seller. The basic, novel theoretic possibility introduced into value theory with the introduction of personalized trading—the trading of personalized commodities—is that price discrimination over quantity may occur under perfect competition. Theorems on the existence and optimality of competitive equilibria under discriminatory pricing are proved.     

Sequential Markets: An Experimental Investigation of Clower's Dual-Decision Hypothesis

Countless experimental studies have shown that markets converge quickly and efficiently to the competitive outcome under many trading institutions, particularly the double auction mechanism. This creates difficulties for Keynesian stories of unemployment creation—which suggest a noncompetitive outcome in an essentially competitive world. Such stories were popular in the late 1960s and 1970s. One of these stories—the dual decision hypothesis of Clower—was seen then as the beginning of a story of unemployment. This article reports the results of an experiment designed to test this hypothesis. Specifically, we set up an experiment in which there are two sequential double-auction markets, in the first of which one good (labour) is traded, after which the second market (goods) is opened and the second good traded. We compare the outcome of our experiment with that of the competitive theory. One general finding is that not enough trade takes place in the two markets. In other words, the usual finding that competitive equilibrium is achieved in double-auction markets is not replicated in this sequential setting. This revised version was published online in August 2006 with corrections to the Cover Date.     

Generous actors,selfish actions: markets with other-regarding preferences

This paper points out that classical competitive outcomes arise in two different market environments even if agents have non-classical preferences. Consumers with separable, other-regarding preferences behave as if they have classical preferences in competitive equilibrium. These outcomes need not be efficient, but under plausible conditions will be efficient following a redistribution of income. In simple double-auction environments competitive outcomes arise under a wide range of assumptions on preferences even without assuming separability. I discuss the importance of the domain of definition of preferences and how the preferences present in the economy influence the performance of the trading institution.

An experimental examination of the house money effect in a multi-period setting

There is evidence that risk-taking behavior is influenced by prior monetary gains and losses. When endowed with house money, people become more risk taking. This paper is the first to report a house money effect in a dynamic, financial setting. Using an experimental method, we compare market outcomes across sessions that differ in the level of cash endowment (low and high). Our experimental results provide support for a house money effect. Traders’ bids, price predictions, and market prices are influenced by the amount of money that is provided prior to trading. However, dynamic behavior is difficult to interpret due to conflicting influences. JEL Classification C91 · C92 · D80 The views expressed here are those of the authors and not necessarily those of the Federal Reserve Bank of Atlanta or the Federal Reserve System.     

A computational analysis of core convergence in a multiple equilibria economy

We examine the structure of the core of a trading economy with three competitive equilibria as the number of traders (N) is varied. The core first splits into two pieces at N=5 and then splits a second time into three pieces at N=12. Both of these splits occur not at a point but as a contiguous gap. We find that the speed of convergence of the core toward the three competitive equilibria is not uniform but when N is large, the convergence rate is approximately of the order 1/N.     

Search cost,trading strategies and optimal market structure

The theory of Walrasian equilibrium yields a set of prices at which the aggregate competitive demand for each commodity equals its aggregate competitive supply. However, even at equilibrium prices the theory of competitive equilibrium does not explicitly offer explanation regarding the manner in which trades are actually executed. This paper considers a model where trade takes place in a decentralized fashion and examines in a dynamic game-theoretic framework, the role of social institution of money and markets in facilitating exchange. The steady state Nash equilibrium derived in the paper demonstrates how, depending on the level of transaction costs associated with a market setup (synonymously, trading posts to exchange possible pairs of goods) appropriate monetary trade emerges, which like a hub and spoke network (Starr and Stinchcombe, 1999) makes some markets non-functioning and in equilibrium only the markets having trade through the medium of exchange continue to exist. However, despite the obvious advantages of a market setup in reducing search costs, pure random search for a complementary trading partner (as considered by Ostroy and Starr, 1974; Kiyotaki and Wright , 1989; and others) prevails in many economies, especially, in many developing economies. This paper models this feature of developing economies by introducing differences in transaction costs across agents and shows why sustainable equilibria might exist exhibiting random search for certain commodities even in the presence of established markets.     

Some Basic Economics of Carbon Taxes

This article asks three questions. First, how do carbon taxes drive economic and environmental outcomes? Second, what is the appropriate economic base on which carbon taxes should be levied? Finally, how well does a carbon tax deliver economic and environmental outcomes compared to a comparable emissions trading scheme?     

Competitive equilibrium when preferences change over time

Summary. We show the existence of a competitive equilibrium in an economy with many consumers whose preferences may change over time. The demand correspondence of an individual consumer is determined by the set of subgame-perfect equilibrium outcomes in his intrapersonal game. For additively separable preferences with concave period utility functions that are unbounded above, this demand correspondence will satisfy the usual boundary conditions. Whenever consumers can recall their own mixed actions, this correspondence is convex-valued. This ensures the existence of a symmetric competitive equilibrium.Received: 29 July 2004, Revised: 17 November 2004, JEL Classification Numbers: D51, D91, C73. Correspondence to: Thomas MariottiWe thank Michele Piccione for useful comments and suggestions. The views expressed herein are those of the authors and not necessarily those of the Federal Reserve Bank of Minneapolis or the Federal Reserve System.     

Learning to collude: An experiment in convergence and equilibrium selection in oligopoly

The paper considers a simple oligopoly model where firms know their own and the average pay-off in the industry. Firms choose decision rules for trading. The theory predicts that there are three types of Nash equilibria in this game (collusive, Cournot and Stackelberg). Our experiments test the selection process. We find that there is clear evidence of convergence to an equilibrium, and whilst both Cournot and collusive outcomes were selected, the collusive equilibrium is more common. The experimental results also give insights into the process of individual learning, confirming that subjects follow aspiration rules rather than reinforcement rules.     

Does money impede convergence?

Inspired by Clower’s conjecture that the necessity of trading through money in monetised economies might hinder convergence to competitive equilibrium, and hence, for example, cause unemployment, we experimentally investigate behaviour in markets where trading has to be done through money. In order to evaluate the properties of these markets, we compare their behaviour to behaviour in markets without money, where money cannot intervene. As the trading mechanism might be a compounding factor, we investigate two kinds of market mechanism: the double auction, where bids, asks and trades take place in continuous time throughout a trading period; and the clearing house, where bids and asks are placed once in a trading period, and which are then cleared by an aggregating device. We thus have four treatments, the pairwise combinations of non-monetised/monetised trading with double auction/clearing house. We find that: convergence is faster under non-monetised trading, implying that the necessity of using money to facilitate trade hinders convergence; that monetised trading is noisier than non-monetised trading; and that the volume of trade and realised surpluses are higher with the double auction than the clearing house. As far as efficiency is concerned, monetised trading lowers both informational and allocational efficiency, and while the double auction outperforms the clearing house in terms of allocational efficiency, the clearing house is marginally better than the double auction in terms of informational efficiency when trade is through money. Crucially we confirm the conjecture that inspired these experiments: that the necessity to use money in trading hinders convergence to competitive equilibrium, lowers realised trades and surpluses, and hence may cause unemployment.     

Corporate insurance with optimal financial contracting

Summary. This paper attemps to rationalize the use of insurance covenants in financial contracts, and shows how external financing generates a demand for insurance by risk-neutral entrepreneurs. In our model, the entrepreneur needs external financing for a risky project that can be affected by an accident during its realization. Accident losses and final returns are private information to the firm, but they can be evaluated by two costly auditing technologies. We derive the optimal financial contract: it is a bundle of a standard debt contract and an insurance contract with franchise, trading off bankruptcy costs vs auditing costs. We then analyze how this optimal contract can be achieved by decentralized trading on competitive markets when insurance and credit activities are exogenously separated. With additive risks, the insurance contract involves full coverage above a straight deductible. We interpret this result by showing how our results imply induced risk aversion for risk-neutral firms. Received: December 14, 1998; revised version: August 11, 1999     

Asset trading volume in a production economy

Judd et al. (J Finance 63: 2203–2217, 2003) show that the stationary Lucas tree model cannot generate nontrivial asset trading: Heterogenous agents will optimally choose a fixed portfolio after initial rebalancing. This paper explores asset trading volume in production economies with heterogeneous agents and dynamically complete market structures. We establish a recursive version of the Negishi approach to prove the existence of a competitive equilibrium. Furthermore, we develop a general method to solve for equilibrium portfolios in production economies within a fairly general set of complete market structures. We thus establish the theoretical reasons why production economies in general generate a nontrivial volume of asset trading even if heterogeneity of the agents is kept to a minimum. We would like to thank W. Brock, D. DeJong and, especially, H. Ennis for comments and suggestions. We also thank seminar participants at Di Tella and San Andrés Universities (Argentina), the Institute for Advanced Studies (Austria), SED Meetings 2005 (Budapest) and SAET Conference 2005 (Vigo).     

Price dynamics in an exchange economy

The pure exchange model is the foundation of the neoclassical theory of value, yet equilibrium predictions and price adjustment dynamics for this model remained untested prior to the experiment reported in this paper. With the exchange economy replicated several times, prices and allocations in most experiment sessions adjust toward the competitive equilibrium in continuous double auction trading, though adjustment is much slower than in previous commodity flow (or perishable good) double auction market experiments. Price adjustment is evaluated by comparing its extent within each market replication (or trading period) to its extent across trading periods. More price adjustment occurs within trading periods than across trading periods, so price adjustment data are evaluated with the disequilibrium Hahn process model (Hahn and Negishi in Econometrica 30:463–469, 1962) of within-period trades. This paper introduces a stochastic version the Hahn process model and demonstrates that a linear approximation to this stochastic model yields an autoregressive process with a near unit root when the adjustment rate is low. In effect, the autoregressive price adjustment model studied extensively by time series econometricians over the past 30 years can be viewed as a reduced form of a stochastic disequilibrium exchange economy price adjustment model. Estimation of the model demonstrates that price adjustment in the exchange economy experiment is considerably slower than in economies without income effects, which suggests that the price discovery process may be a significant factor in the slow adjustment documented by applied econometricians.     

Marketmaking in the Laboratory: Does Competition Matter?

This paper is the first experimental study of the effects of competition and adverse selection on the performance of market maker (MM-) markets. Information distribution may is either symmetric or heterogeneous. MM-markets are either monopolistic (the specialist markets), or competitive (the multi MM-market). Welfare comparisons are with respect to a continuous double auction (DA-) market. Informed subjects receive an imperfect signal of the true state of the world. We find three main results. First, competition among market makers significantly reduces the bid-ask spread, and increases transaction volume. Second, competition among market makers induces competitive undercutting, yielding net trading losses for market makers as a group in most periods. Third, from the perspective of uninformed traders, a competing MM-regime is optimal, since it minimizes their expected trading losses.     

Prices, Delay, and the Dynamics of Trade

We characterize the dynamics of trading patterns and market composition when trade is bilateral, finding a trading partner is costly, prices are determined by bargaining, and preferences are private information. We show that equilibrium is inefficient and exhibits delay as sellers price discriminate between buyers with different values. As frictions vanish, transaction prices are asymptotically competitive and the welfare loss of inefficient trading approaches zero, even though the trading patterns continue to be inefficient and delay persists. Journal of Economic Literature Classification Numbers: D40, D50.     

Individual Differences in the Disposition Effect

The authors model the role of personality traits in explaining the disposition effect building on realization utility theory and Big 5 model and moving from an aggregate level to interindividual differences. The experimental analysis, combining NEO Revised Personality Inventory measures with individual financial data from a trading simulation run by 230 individuals in China and Italy, shows that the disposition effect is driven by 2 distinct psychological processes, one related to holding losers and the other to selling winners. These 2 behavioral mechanisms are uncorrelated and influenced by different personality traits. Controlling for different demographic variables, the authors show (a) a greater sensitivity of the rewarding system that motivates “extroverts” to quickly sell the stock at gain to receive a burst of utility; (b) a tendency for “conscientious” subjects to suppress impulsivity, patiently waiting for higher cumulative returns; and (c) the importance of “openness to experience” to better value information to achieve higher outcomes.