Bayesian analysis of coefficient instability in dynamic regressions

This paper proposes a Bayesian regression model with time-varying coefficients (TVC) that makes it possible to estimate jointly the degree of instability and the time-path of regression coefficients. Thanks to its computational tractability, the model proves suitable to perform the first (to our knowledge) Monte Carlo study of the finite-sample properties of a TVC model. Under several specifications of the data generating process, the proposed model’s estimation precision and forecasting accuracy compare favourably with those of other methods commonly used to deal with parameter instability. Furthermore, the TVC model leads to small losses of efficiency under the null of stability and it is robust to mis-specification, providing a satisfactory performance also when regression coefficients experience discrete structural breaks. As a demonstrative application, we use our TVC model to estimate the exposures of S&P 500 stocks to market-wide risk factors: we find that a vast majority of stocks have time-varying risk exposures and that the TVC model helps to forecast these exposures more accurately.time-varying regression, coefficient instability

Retail sector concentration and price dynamics in the euro area: a regional analysis

We conduct a regional analysis of the relationship between market concentration and price dynamics in the grocery retail sector, focusing on a sample of five categories of goods belonging to the 12 COICOP aggregation and on a panel of countries that includes Germany, Spain, Finland, Italy, Austria and Portugal. Using a unique census-type dataset on retailers, we construct Herfindahl-Hirschman indices of concentration at the buying group, parent company and individual shop level for a sample of 118,540 large grocery stores and we study the association between these measures and regional price changes. Our results point to a positive association between retail market concentration and price growth in food and beverages, alcohol and tobacco and miscellaneous goods in the time span 2003-2010 at the buying, parental group and store level for the pooled sample of countries. The relation reverses sign for clothing and footwear and household equipment. This evidence is robust to different specifications of concentration indices.Market concentration, price dynamics, buying group, parent company, regional Herfindahl-Hirschman indices.

Directed Matching with Endogenous Markov Probability: Clients or Competitors?

We analyze the problem of strategic poaching of consultants by clients with particular reference to the business consulting industry. This article presents a market equilibrium in a mixed economy where three categories of agents, consulting groups, client firms and consultants strategically interact with each other. At each date the consulting group faces a new client firm that requires a task to be implemented. We show that under very general conditions, when a matching pair of clients and consultants meets, a dominant strategy will be played, where the consultant is captured by the client and the consulting group matches (whenever possible) the client's request. The novelty of this model is that the quality of the consulting services does not only depend on the consulting group's assignment strategy , but also on the capturing behavior of the clients. In this sense, the clients impose a consumption externality on each other, which is a source of inefficiency in this otherwise competitive market.strategic poaching, two-sided matching, Nash bargaining, consumption externality.

Report on trends in the Italian productive system

In the last decade the Italian economy has underperformed compared both with the previous decades and with the main European countries. It is widely acknowledged that this evolution reflects unresolved structural problems, which have become more urgent in view of the major changes in the world economy (the new technological paradigm, globalization, European economic integration). The goal of the Report is to make a critical survey of all the empirical analyses on the Italian economy and to derive policy suggestions. The evolution of Italy’s productive system is examined from a long-run perspective, highlighting weaknesses and possible signs of recovery and elaborating on the systemic features that may have negatively affected growth performance directly or indirectly through the above exogenous shocks. The focus, mostly but not exclusively microeconomic, emphasizes the considerable heterogeneity of firms, a crucial element for identifying the factors that affect economic growth.growth, productivity, market structure, firm heterogeneity