Spatial interdependence in cost efficiency and local government optimal size: The case of Italian municipalities

This study provides an original approach to empirically determine the optimal size of municipalities for efficient social service delivery in Italy, accounting for spatial spillover effects across municipalities as well as endogeneity between the output provided and its cost. A highly disaggregated and up-to-date database of Italian municipalities is used to estimate, through endogenous spatial frontier of Kutlu et al. (2020), the minimum costs. In municipalities with population ranging from 2000 to 3500 economies of scale in social service provision emerge, exhibiting cost-optimality. This outcome is completely ignored in some Regional government where financing criteria are based on historical, non-public, and ex-post repayment criteria.     

Too similar to combine? On negative weights in forecast combination

This paper provides the first thorough investigation of the negative weights that can emerge when combining forecasts. The usual practice in the literature is to consider only convex combinations and ignore or trim negative weights, i.e., set them to zero. This default strategy has its merits, but it is not optimal. We study the problem from various angles, and the main conclusion is that negative weights emerge when highly correlated forecasts with similar variances are combined. In this situation, the estimated weights have large variances, and trimming reduces the variance of the weights and improves the combined forecast. The threshold of zero is arbitrary and can be improved. We propose an optimal trimming threshold, i.e., an additional tuning parameter to improve forecasting performance. The effects of optimal trimming are demonstrated in simulations. In the empirical example using the European Central Bank Survey of Professional Forecasters, we find that the new strategy performs exceptionally well and can deliver improvements of more than 10% for inflation, up to 20% for GDP growth, and more than 20% for unemployment forecasts relative to the equal-weight benchmark.     

Multivariate risk aversion utility,application to ESG investments

This paper uses the concept of multivariate or multi-attributive utility to attach different risk aversion levels to different sources of wealth (e.g. sectors, stocks, asset classes). In this context, we address the topic of environmental, social, and corporate governance (ESG) investments from the perspective of an investor with different risk aversion levels to green and brown stocks. We obtain closed-form solutions for the optimal allocations, value function, and wealth equivalent losses (WEL) from suboptimal choices. The numerical analysis demonstrates the significant increase, of up to 33%, in green investments when accounting for a differential in risk aversions levels, with up to 65% in WEL when using same risk-aversion levels.¹     

Optimal growth under model uncertainty

The optimal growth of a wealth process toward a goal is studied under ambiguous markets with first- and second-order moment uncertainties relating to stock returns. Optimal strategies and value functions are solved explicitly. A verification theorem is proved to show that the results solve the original stochastic control problem. Quantitative analyses of the investment strategies indicate that a rational individual with ambiguity aversion reduces market participation when return and volatility are uncorrelated, while there is an exception for synchronous return and volatility. The welfare of shorting a discounted reward is computed, which demonstrates that in an ambiguous pricing economy, investors can generate a positive premium via appropriate asset allocations.     

证券投资基金规模适度性研究——基于中国市场的证据

随着社保、养老金等中长期资金的大规模入市,中国公募基金规模面临更快扩张,那么基金规模究竟是可以无限扩张还是存在制约？本文研究发现,基金规模扩张会受到基金经理与投资者之间的委托代理冲突、边际规模报酬递减、投资者大规模赎回的制约。基于此,本文提出了基金管理规模适度区间的概念及其相应计量模型,并借此对2011—2019年间中国公募基金市场规模的适度性进行实证判断和检验,结果显示:(1)中国公募基金的平均管理规模在2015年之前过大,2016年之后趋向适度,而在2019年出现偏小现象。(2)中国基金市场规模适度区间的上、下限呈现逐年减小趋势,但二者的差值,即适度性区间的宽度却逐年增加。(3)规模适度基金的业绩表现远好于规模不足和规模过大两类基金,但市场上的规模适度基金占比则小于另外两类基金。最后,本文就如何提升公募基金,尤其是对安全性和盈利性要求更高的养老保险基金的规模适度性提出了相应对策建议。     

Hotelling and recycling

We study the exploitation of recyclable exhaustible resources such as metals that are crucial for the energy transition or phosphorus that is crucial for agricultural production. We use a standard Hotelling model of resource exploitation that includes a primary sector and a recycling sector. We study two polar cases: competitive and monopolistic extraction. We show that, when the primary sector is competitive, the Hotelling’s rule holds and the price of the recyclable resource increases over time. We then show a new reason why the price of an exhaustible resource may decrease: when the primary sector is monopolistic, the primary producer has incentives to delay its production activities in order to delay recycling. As a consequence, the price path of the recyclable resource may be U-shaped. Numerical simulations reveal that the monopolist has an incentive to delay extraction when the recoverability rate is high (because more recycled goods are produced) or when the recoverability rate is low (when fewer recycled goods are expected to be produced in the future). As a consequence, the date of exhaustion of the virgin resource is further away in time for high and low levels of recoverability than for intermediate levels.