Agent-based simulation of power exchange with heterogeneous production companies

Since early nineties, worldwide production and distribution of electricity has been characterized by a progressive liberalization. The state-owned monopolistic production of electricity has been substituted by organized power exchanges (PEs). PEs are markets which aggregate the effective supply and demand of electricity. Usually spot-price market are Day Ahead Market (DAM) and are requested in order to provide an indication for the hourly unit commitment. This first session of the complex daily energy market collects and orders all the offers, determining the market price by matching the cumulative demand and supply curves for every hour of the day after according to a merit order rule. Subsequent market sessions (also online) operate in order to guarantee the feasibility and the security of this plan. The electric market is usually characterized by a reduced number of competitors, thus oligopolistic scenario may arise. Understanding how electricity prices depend on oligopolistic behavior of suppliers and on production costs has become a very important issue. Several restructuring designs for the electric power industry have been proposed. Main goal is to increase the overall market efficiency, trying to study, to develop and to apply different market mechanisms. Auction design is the standard domain for commodity markets. However, properties of different auction mechanism must be studied and determined correctly before their appliance. Generally speaking, different approaches have been proposed in the literature. Game theory analysis has provided an extremely useful methodology to study and derive properties of economic "games", such as auctions. Within this context, an interesting computational approach, for studying market inefficiencies, is the theory of learning in games. This methodology is useful in the context of infinitely repeated games. This paper investigates the nature of the clearing mechanism comparing two different methods, i.e., discriminatory and uniform auctions. The theoretical framework used to perform the analysis is the theory of learning in games. We consider an inelastic demand faced by sellers which use learning algorithms to understand proper strategies for increasing their profits. We model the auction mechanism in two different duopolistic scenario, i.e., a low demand situation, where one seller can clear all the demand, and a high demand condition, where both sellers are requested. Moreover, heterogeneity in the linear cost function is considered. Consistent results are achieved with two different learning algorithmsAgent-based simulation; power-exchange market; market power, reinforcement learning, electricity production costs

Macroprudential policies in an agent-based artificial economy

Basel III is a recently-agreed regulatory standard for bank capital adequacy with focus on the macroprudential dimension of banking regulation, i.e., the system-wide implications of banks' lending and risk. An important Basel III provision is to reduce procyclicality of present banking regulation and promote countercyclical capital buffers for banks. The Eurace agent-based macroeconomic model and simulator has been recently showed to be able to reproduce a credit-fueled boom-bust dynamics where excessive bank leverages, while benefitting in the short term, have destabilizing effects in the medium-long. In this paper. we employ the Eurace model to test regulatory policies providing time varying capital requirements for banks, based on mechanisms that enforce banks to build up or release capital buffers, according to the overall conditions of the economy. As conditioning variables for these dynamic policies, both the unemployment rate and the aggregate credit growth have been considered. Results show that the dynamic regulation of capital requirements is generally more successful than fixed tight capital requirements in stabilizing the economy and improving the macroeconomic performance.Basel III, macroprudential regulation, agent-based models and simulation

The impact of banks’ capital adequacy regulation on the economic system: an agent-based approach

Since the start of the financial crisis in 2007, the debate on the proper level leverage of financial institutions has been flourishing. The paper addresses such crucial issue within the Eurace arti?cial economy, by considering the effects that different choices of capital adequacy ratios for banks have on main economic indicators. The study also gives us the opportunity to examine the outcomes of the Eurace model so to discuss the nature of endogenous money, giving a contribution to a debate that has grown stronger over the last two decades. A set of 40 years long simulations have been performed and examined in the short (first 5 years), medium (the following 15 years) and long (the last 20 years) run. Results point out a non-trivial dependence of real economic variables such as the Gross Domestic Product (GDP), the unemployment rate and the aggregate capital stock on banks’ capital adequacy ratios; this dependence is in place due to the credit channel and varies significantly according to the chosen evaluation horizon. In general, while boosting the economy in the short run, regulations allowing for a high leverage of the banking system tend to be depressing in the medium and long run. Results also point out that the stock of money is driven by the demand for loans, therefore supporting the theory of endogenous nature of credit money.Agent-based models, banking regulation

Static and dynamic factors in an information-based multi-asset artificial stock market

3noAn information-based multi-asset artificial stock market characterized by different types of stocks and populated by heterogeneous agents is presented. In the market, agents trade risky assets in exchange for cash. Beside the amount of cash and of stocks owned, each agent is characterized by sentiments and agents share their sentiments by means of interactions that are determined by sparsely connected networks. A central market maker (clearing house mechanism) determines the price processes for each stock at the intersection of the demand and the supply curves. Single stock price processes exhibit volatility clustering and fat-tailed distribution of returns whereas multivariate price process exhibits both static and dynamic stylized facts, i.e., the presence of static factors and common trends. Static factors are studied making reference to the cross-correlation of returns of different stocks. The common trends are investigated considering the variance–covariance matrix of prices. Results point out that the probability distribution of eigenvalues of the cross-correlation matrix of returns shows the presence of sectors, similar to those observed on real empirical data. As regarding the dynamic factors, the variance–covariance matrix of prices point out a limited number of assets prices series that are independent integrated processes, in close agreement with the empirical evidence of asset price time series of real stock markets. These results remarks the crucial dependence of statistical properties of multi-assets stock market on the agents’ interaction structure.partially_openopenPonta, Linda*; Pastore, Stefano; Cincotti, SilvanoPonta, Linda; Pastore, Stefano; Cincotti, Silvan

The Relationship between Firm-Specific Return Variation and Price Informativeness: Some Cross-Sectional Evidence

The progressive removal of short-selling constraints in the Chinese stock market provides us with a natural experiment to investigate the relationship between firm-specific return variation (FSRV) and price informativeness. Based on the empirical finding that idiosyncratic volatility is a satisfied proxy for FSRV when the information environment for individual firms improves, we mainly find that the FSRV is negatively related to price informativeness. This negative relationship is robust to alternative model specifications, alternative proxies for price informativeness, and alternative estimation windows. Generally speaking, our results complement the extant literature on the mixed relationships between FSRV and price informativeness by providing cross-sectional evidence

Macroprudential policies in an agent-based artificial economy

Basel III is a recently-agreed regulatory standard for bank capital adequacy with focus on the macroprudential dimension of banking regulation, i.e., the system- wide implications of banks’ lending and risk. An important Basel III provision is to reduce procyclicality of present banking regulation and promote countercyclical capital buffers for banks. The Eurace agent-based macroeconomic model and sim- ulator has been recently showed to be able to reproduce a credit-fueled boom-bust dynamics where excessive bank leverages, while benefitting in the short term, have destabilizing effects in the medium-long term. In this paper we employ the Eu- race model to test regulatory policies providing time varying capital requirements for banks, based on mechanisms that enforce banks to build up or release capital buffers, according to the overall conditions of the economy. As conditioning variables for these dynamic policies, both the unemployment rate and the aggregate credit growth have been considered. Results show that the dynamic regulation of capital requirements is generally more successful than fixed tight capital requirements in stabilizing the economy and improving the macroeconomic performance

Why do we need agent-based macroeconomics?

We are entering the third decade of the twenty-first century with profound uncertainties and crucial challenges for the world economy. Phenomena like climate change, digital transformation, migration, demographic changes, and the ongoing COVID pandemic need to be understood and promptly addressed. We argue that the agentbased approach in economics is well suited to tackle these topics, because of its capacity to integrate the \u201cmicro\u201d and \u201cmacro\u201d dimensions by modelling the network of interactions among heterogeneous economic agents and their aggregate outcomes. This paper explains why the agent-based methodology is needed to overcome the limitations of the neoclassical approach in economics, which has not been able to properly address those challenges. To do so, the paper retraces the main stages of the scientific evolution in a general historical and epistemological perspective, showing how the paradigm of reductionism, which led to extraordinary advances after the scientific revolution of the seventeenth century, is less effective when addressing the main challenges ahead. On the other hand, the sciences of chaos theory and complex systems can provide the economic discipline with more suitable instruments to face those challenges. Finally, the paper briefly presents the contributions of the special issue, which use applications of agent-based models to study the main problems of our times

Endogenous credit dynamics as source of business cycles in the EURACE model

The paper investigates the relationship between the amount of credit money in the economy and the variability of output and prices in the EURACE model. First we examine if the decision about dividends payment by the firms can affect this variability, then we adopt the policy measure of quantitative easing, that has been largely used by the Fed and the Bank of England during the recent crisis, in order to understand its effect on economic instability. Results show the emer- gence of endogenous business cycles which are mainly due to the interplay between the real economic activity and its financing through the credit market. In particular, the amplitude of the business cycles strongly raises when the fraction of earnings paid out by firms as dividends is higher, that is when firms are more constrained to borrow credit money to fund their activity

Monetary Incentives in Italian Public Administration: A Stimulus for Employees? An Agent-Based Approach

The paper, focusing on the context of Public Administration (PA), addresses the effects of monetary incentives in employees' performance. In the Italian PA, the monetary incentives are distributed according to the D.L.150/09 (i.e., the monetary incentives are divided among the employees according to the employees' performance) which is based on the rank order tournament. The paper investigates if this mechanism has positive and sustainable impacts on the employees' performance in the short, middle, and long term. The employees' performance has been modeled as a function of ability and motivation. The results of the computational experiments show a positive impact of the monetary incentives, distributed according to merit criteria, on the employees' performance in the short, middle, and long term