Structural estimation of behavioral heterogeneity

We develop a behavioral asset pricing model in which agents trade in a market with information friction. Profit‐maximizing agents switch between trading strategies in response to dynamic market conditions. Owing to noisy private information about the fundamental value, the agents form different evaluations about heterogeneous strategies. We exploit a thin set—a small sub‐population—to point identify this nonlinear model, and estimate the structural parameters using extended method of moments. Based on the estimated parameters, the model produces return time series that emulate the moments of the real data. These results are robust across different sample periods and estimation methods.     

It’s worth a shot: urban density,endogenous vaccination decisions,and dynamics of infectious disease

Journal of Economic Interaction and Coordination - We develop an agent-based model of vaccine decisions across a heterogeneous network model with urban and rural regions. In the model, agents make...     

The stock–bond comovements and cross-market trading

We propose an asset pricing model with heterogeneous agents allocating capital to the stock and bond markets to optimize their portfolios, utilizing the dynamic interaction between the two markets. While some agents focus on the stock market and have more expertise in it, the others specialize in the bond market. Based on their comparative advantages in a particular market, heterogeneous agents constantly revise their investment portfolios by taking into account the time-varying stock–bond return comovements and the changing market conditions. Agents׳ collective investment behavior shapes the stock–bond interlinkage, which feedbacks on their subsequent capital allocations. Using monthly US stock and bond data from January 1990 to June 2014, we estimate the vector autoregression model with threshold and Markov switching mechanisms. We find evidence in support of flight-to-quality and show that it is mainly driven by the technical traders who actively sell stocks and buy bonds during periods of high market uncertainty.     

Fundamentalists vs. chartists: Learning and predictor choice dynamics

In a simple, forward looking univariate model of price determination we investigate the evolution of expectations dynamics in the presence of two types of agents: fundamentalists and chartists. In particular, we combine evolutionary selection among heterogeneous classes of models through predictor choice dynamics based on a logit model, with adaptive learning in the form of parameters updating within each class of rules. We find that, for different parameterizations, it can happen that fundamentalists drive chartists completely out of the market or vice versa, and also that heterogeneous equilibria in which fundamentalists and chartists coexist are possible. Interestingly, though, only equilibria in which fundamentalists outperform chartists turn out to be adaptively learnable by agents.     

Uncertainty about fundamental,pessimistic and overconfident traders: a piecewise-linear maps approach

Decisions in Economics and Finance - We analyze a financial market model with heterogeneous interacting agents where fundamentalists and chartists are considered. We assume that fundamentalists are...     

Asset price dynamics with heterogeneous beliefs and local network interactions

In this paper we investigate the effects of network topologies on asset price dynamics. We introduce network communications into a simple asset pricing model with heterogeneous beliefs. The agents may switch between several belief types according to their performance. The performance information is available to the agents only locally through their own experience and the experience of other agents directly connected to them. We model the communications with four commonly considered network topologies: a fully connected network, a regular lattice, a small world, and a random graph. The results show that the network topologies influence asset price dynamics in terms of the regions of stability, amplitudes of fluctuations and statistical properties.     

Solving the incomplete market model with aggregate uncertainty using a perturbation method

We use a perturbation method to solve the incomplete markets model with aggregate uncertainty described in den Haan et al. [Computational suite of models with heterogeneous agents: incomplete markets and model uncertainty. Journal of Economic Dynamics & Control, this issue]. To apply that method, we use a “barrier method” to replace the original problem with occasionally binding inequality constraints by one with only equality constraints. We replace the structure with a continuum of agents by a setting in which a single infinitesimal agent faces prices generated by a representative-agent economy. We also solve a model variant with a large (but finite) number of agents. Our perturbation-based method is much simpler and faster than other methods.     

Investments in education and welfare in a two-sector,random matching economy

We consider a random matching model where heterogeneous agents choose optimally to invest time and real resources in education. Generically, there is a steady state equilibrium where some agents, but not all of them, invest. Regular steady state equilibria are constrained inefficient in a strong sense. The Hosios (1990) condition is neither necessary nor sufficient for constrained efficiency. We also provide restrictions on the fundamentals sufficient to guarantee that equilibria are characterized by overeducation (or undereducation), present some results on their comparative statics properties, and discuss the nature of welfare improving policies.     

Contests over joint production on networks

We consider a network of heterogeneous agents where each edge represents a two‐player contest between the respective nodes. In these bilateral contests, agents compete over an endogenous prize jointly produced using their own contest efforts. We provide a necessary and sufficient condition for the existence of Nash equilibrium and characterize the equilibrium total effort for every agent. Our model has insightful results regarding the network type, that is, depending on whether the network is bipartite or nonbipartite. Finally, considering the sum of all expected utilities as an efficiency notion, we investigate the optimal network structure.     

Career Tournaments

This paper studies a model of career concerns where (besides agents having different ability levels) principals are heterogeneous. Two types of heterogeneity are considered: principals can differ in their productivities, and in the visibility of the agents working for them. Productivity differences result in convex wage profiles and generate assortative matching between principals and agents. Visibility differences, on the other hand, affect the mobility and career prospects of agents, and can generate nonassortative matching. We characterize the equilibrium in this market, derive implications for the behavior of agents, and examine the incentives to invest in increasing productivity and visibility.     

Validating an agent-based model of the Zipf׳s Law: A discrete Markov-chain approach

This study discusses the validation of an agent-based model of emergent city systems with heterogeneous agents. To this end, it proposes a simplified version of the original agent-based model and subjects it to mathematical analysis. The proposed model is transformed into an analytically tractable discrete Markov model, and its city size distribution is examined. Its discrete nature allows the Markov model to be used to validate the algorithms of computational agent-based models. We show that the Markov chains lead to a power-law distribution when the ranges of migration options are randomly distributed across the agent population. We also identify sufficient conditions under which the Markov chains produce the Zipf׳s Law, which has never been done within a discrete framework. The conditions under which our simplified model yields the Zipf׳s Law are in agreement with, and thus validate, the configurations of the original heterogeneous agent-based model.     

Solving the incomplete markets model with aggregate uncertainty using the Krusell–Smith algorithm

This paper studies the properties of the solution to the heterogeneous agents model in Den Haan et al. [2009. Computational suite of models with heterogeneous agents: incomplete markets and aggregate uncertainty. Journal of Economic Dynamics and Control, this issue]. To solve for the individual policy rules, we use an Euler-equation method iterating on a grid of pre-specified points. To compute the aggregate law of motion, we use the stochastic-simulation approach of Krusell and Smith [1998. Income and wealth heterogeneity in the macroeconomy. Journal of Political Economy 106, 868–896]. We also compare the stochastic- and non-stochastic-simulation versions of the Krusell–Smith algorithm, and we find that the two versions are similar in terms of their speed and accuracy.     

Heterogeneous expectations and debt in a growth model for a small open economy

We extend an aggregative growth model for a small open economy by developing a framework in which boundedly rational agents raise credit in proportion to their expected income. Moreover, these agents are heterogeneous in the sense that they switch between an extrapolative and a regressive forecasting rule with respect to perceived market circumstances. Using a mixture of analytical and numerical tools, we attempt to describe the characteristics of our model’s dynamical system. Our results then suggest that self-fulfilling short-run expectations do not only have important consequences for fluctuations in economic activity but are also a source of simple endogenous dynamics.     

A cobweb model of land-use competition between food and bioenergy crops

We present a model of interacting cobweb markets and apply it to land-use competition between food and bioenergy crops. In our model the markets are interlinked on the supply side by the limited availability of land. Therefore, instabilities are transferred between the markets and we find that bioenergy demand affects food price volatility. The agents in the model have heterogeneous production capacities, representing variation in global land quality. When we allow agents to choose price predictor, we find that a more sophisticated (but costly) predictor is concentrated to some key parcels of land, which enables the system to reduce instability significantly. The system can also be brought closer to a stable state by introducing costs for changing production type, but it may then be shifted away from the optimum situation predicted by the corresponding equilibrium model.     

Social distance,heterogeneity and social interactions

A crucial ingredient in social interaction models is the structure of peer groups, which link individuals with similar characteristics. We propose and study a dynamic binary choice model with social interactions in which heterogeneity of peer group effects is modeled introducing diversity in individual characteristics and linking pairwise influences to a social distance between individuals. Our framework allows for mimetic as well as anti-mimetic interactions and a heterogeneous structure of peer groups across individuals. Dynamic equilibria are studied in the limit when the number of agents is large. We show that the model exhibits multiple equilibria resulting from conflicts between various group pressures the individuals are subjected to. We study in particular the correlation in the population at equilibrium between the characteristics of the agents and their decisions: this quantity has an interesting empirical interpretation and solves a simple analytical equation when the number of agents is large. Finally we discuss the empirical content of the model and present a consistent estimator for the parameter describing which is consistent for any typical population regardless of the structure of individual characteristics.     

Cross-section instability in financial markets: impatience,extrapolation, and switching

Decisions in Economics and Finance - This paper presents a stylized model of interaction among boundedly rational heterogeneous agents in a multi-asset financial market to examine how agents’...     

Smart predictors in the heterogeneous agent model

We extend the original heterogeneous agent model by introducing the concept of smart traders. The idea of smart traders is based on the endeavor of market agents to estimate future price movements. The main result of the simulations is that the probability distribution functions of the price deviations change significantly with an increasing number of smart traders in the model. We also find that the Hurst exponent is significantly increasing with an increasing number of smart traders in the simulations. Hence the introduction of the smart traders concept into the model results in significantly higher persistence of the simulated price deviations.     

The equity implications of e‐commerce: A note

We develop a simple model with heterogeneous agents and search frictions to study how increases in matching intensity between buyers and retailers as a result of e‐commerce determine the level of income inequality among retailers. Our findings indicate that a reduction in search frictions leads to higher inequality and induces buyers to purchase goods and services only from specialized retailers.     

Booms,busts and behavioural heterogeneity in stock prices

We estimate a behavioural heterogeneous agents model with boundedly rational traders who know the fundamental stock price, but disagree about the persistence of deviations from the fundamental. Some agents (fundamentalists) believe in mean-reversion of stock prices, while others (chartists) expect a continuation of the trend. Agents gradually switch between the two rules, based upon their relative performance, leading to self-reinforcing regimes of mean-reversion and trend-following. For the fundamental benchmark price we use two well-known models, the Gordon model with a constant risk premium and the Campbell-Cochrane consumption-habit model with a time-varying risk premium. We estimate a two-type switching model using U.S. stock prices until 2016Q4. The estimations show an improvement over representative agent models that is both statistically and economically significant. Our model suggests that behavioural regime switching strongly amplifies booms and busts, in particular, the dot-com bubble and the financial crisis in 2008.     

Behavioural heterogeneity and shift-contagion: Evidence from the Asian crisis

In this paper, we propose an empirical model based on the heterogeneous agents literature. Price changes are induced by fundamental, technical, and international factors. The model is estimated for Hong Kong and Thailand surrounding the Asian crisis. We find that the three sources are relevant and that their relative price impact fluctuates conditional on price impact in the previous period. Results imply that the crisis is triggered in Thailand due to an increased focus on the fundamental price, followed by an increase in chartism and finally aggravated by a focus on foreign developments. Furthermore, the crisis deepens in Hong Kong because of increased attention for foreign markets.