股价信息含量与投资-股价敏感性——基于融资融券的准自然实验

本文利用2006-2015年间的数据研究了融资融券对投资-股价敏感性的影响。利用融资融券作为股价信息含量的一个外生冲击变量,本文研究发现,我国A股市场确实存在反馈效应,融资融券政策的实施增强了标的公司投资-股价敏感性,这个结论在采用倾向得分模型(PSM)配对后依然成立,说明融资融券使股价融入了更多有利于管理层投资决策的信息。其次,融资融券对投资-股价敏感性的影响在机构投资者比例高、流动性高、处于新兴行业的这类管理层反馈效应更强的股票组中更显著。参照以往研究考虑了融资约束对反馈效应的调节作用,同样发现融资融券对投资-股价敏感性的影响在国有企业和规模较大的企业组中更显著。最后,融资融券交易规模越大,投资对股价的敏感性越强。     

Trees and decisions

Summary. The traditional model of sequential decision making, for instance, in extensive form games, is a tree. Most texts define a tree as a connected directed graph without loops and a distinguished node, called the root. But an abstract graph is not a domain for decision theory. Decision theory perceives of acts as functions from states to consequences. Sequential decisions, accordingly, get conceptualized by mappings from sets of states to sets of consequences. Thus, the question arises whether a natural definition of a tree can be given, where nodes are sets of states. We show that, indeed, trees can be defined as specific collections of sets. Without loss of generality the elements of these sets can be interpreted as representing plays. Therefore, the elements can serve as states and consequences at the same time.Received: 23 January 2003, Revised: 2 November 2003, JEL Classification Numbers: C72, D70. Correspondence to: Klaus RitzbergerWe are grateful to Larry Blume, Ariel Rubinstein, Jörgen Weibull, an anonymous referee, and seminar participants at the universities of Vienna, Salamanca, and Heidelberg for helpful comments. Financial support from the Austrian Science Fund (FWF) under project P15281 is also gratefully acknowledged.     

A theory of sequential reciprocity

Many experimental studies indicate that people are motivated by reciprocity. Rabin [Amer. Econ. Rev. 83 (1993) 1281] develops techniques for incorporating such concerns into game theory and economics. His theory is developed for normal form games, and he abstracts from information about the sequential structure of a strategic situation. We develop a theory of reciprocity for extensive games in which the sequential structure of a strategic situation is made explicit, and propose a new solution concept—sequential reciprocity equilibrium—for which we prove an equilibrium existence result. The model is applied in several examples, and it is shown that it captures very well the intuitive meaning of reciprocity as well as certain qualitative features of experimental evidence.     

Rewilding and restoring cultural landscapes in Mediterranean mountains: Opportunities and challenges

Farmland abandonment and the decline of livestock activity in the Mediterranean mountains have resulted in dramatic landscape changes, including the generalized expansion of shrublands and forests, and the homogenization of the old cultural landscapes. This process has a variety of consequences from ecological, geomorphological and hydrological points of view, as well as from the perspectives of land management and public awareness. An intense debate currently surrounds the discussion and evaluation of rewilding (the process of passively allowing woody encroachment, as well as the reintroduction of large mammals) as an opportunity for enhancing biodiversity and restoring original landscapes after centuries of human activity versus ecological restoration (activities leading to the recovery of degraded ecosystems, including clearing and light human activity). There is no clear consensus regarding the best way to improve the ecological relationships and functioning within an ecosystem. Biodiversity and sustainability can be seen under different levels of human pressure and landscape transformation; total farmland abandonment is not always the best alternative, particularly when local inhabitants aim to sustain themselves using local resources. Many geographers and ecologists consider that extensive stockbreeding in a partially open landscape is a rational way to (i) improve landscape organization, (ii) increase flows and turnover within the ecosystems, (iii) increase the diversity of plants and animals that benefit from a relatively light human presence, and (iv) reduce wildfire risk. However, it has proven challenging for land managers and stockbreeders to clear the best old abandoned fields and “construct” a sustainable, balanced landscape that combines forests, shrublands and open lands. Private landowner involvement and support from the general public is crucial for both funding and the long-term maintenance of benefits. The best old fields should be cleared in the context of high-resolution knowledge of the topography, grassland characteristics, grassland cycles and livestock management. Such efforts are likely to be an excellent opportunity to introduce compatibility between light human activity and increases in biodiversity and sustainability for many marginal mountains, where land abandonment and general forest/shrub recovery are the inevitable tendencies. This paper examines some of the contrasting positions of the scientific community regarding the rewilding or ecological restoration of mountain landscapes, and briefly highlights some experiences in which intentional clearing of old abandoned fields has benefited stockbreeding, biodiversity, runoff generation and wildfire risks. Notably, we describe a sub-Mediterranean valley of the Iberian Range, Northern Spain, as an example. In the long term, we find that the intentional clearing of the best old fields allows the slow organization of a final landscape that will be more useful for local inhabitants, thereby helping to reverse human depopulation in these regions.     

卖空限制与收益可预测性——A股融资融券制度的证据

基于A股市场融资和融券余额的巨大差距,本文拓展了Hong et al.(2016)的理论模型,在融券端和融资端分别找到了影响股票收益率的变量:融券比率(融券余额/流通市值)和融资回补天数(融资比率/日均换手率)。进一步,本文利用组合价差法和Fama-MacBeth横截面回归法,实证检验了A股市场中融券比率与融资回补天数解释和预测股票收益率的能力。实证结果表明,在存在融券限制条件下,融券比率相比融券回补天数(融券比率/日均换手率)能更好地代表套利者对股票价格高估程度的看法,根据融券比率构建的等权重多空组合能带来月均1.58%的显著收益;而由于融资约束相对较少,融资回补天数相比融资比率(融资余额/流通市值)能更好地代表套利者对股票价格低估程度的看法,根据融资回补天数构建的等权重多空组合能带来月均1.28%的显著收益。实证结果与本文存在融券数量限制下的理论模型相符,且该收益率不能被多因子模型和常规股票特征所解释。     

Entry,trade costs,and international business cycles

Are firm entry and fixed exporting costs relevant for understanding the international transmission of business cycles? We revisit this question using a model that includes entry, selection to exporting activity, physical capital accumulation and endogenous labor supply. We determine that once the stochastic process for exogenous productivity is calibrated to consider the endogenous dynamics in TFP created by the number of firms and the time series volatility of entry is calibrated to the data, our model yields minimal departures from the Backus et al. (1992) benchmark. The richer model shares all of the successes of the previous model in terms of the volatilities of aggregate quantities, as well as its failures, in terms of replicating patterns of international co-movement and the volatility of international relative prices.     

异质性企业、结构转型与稳定出口

通过构建异质性企业、结构转型和出口增长的二元边际理论模型,本文认为转型国家出口增长主要沿集约边际实现的原因与其农业剩余劳动力有关,农业剩余劳动力越多,出口增长的集约边际越大、扩展边际越小。利用Tobit模型对1995-2009年中国出口到123个国家的HS-6位码贸易数据进行实证分析,在控制其他影响因素的前提下,我国农业剩余劳动力非农转移显著正向影响出口增长集约边际、负向影响扩展边际的效应确实存在。经济规模、贸易成本、人民币升值、区域经济一体化、外部冲击、语言的相通性、政治体制等变量对中国出口增长二元边际的影响机制不完全相同,表明要提高出口增长中的扩展边际比重,出口企业应实施市场多元化战略,将目标市场从传统高收入国家转移到发展中国家来,实现出口的稳定增长。     

旧城改造开发项目的容积率问题研究

随着我国城市化进程的加速推进,不断增长的城市人口与持续升级的功能需求,对现代城市的建设与发展提出了新的要求。旧城改造是提升城市形象和改善人民生活的有效手段。本文在阐述容积率相关概念的基础上,根据投入产出理论,提出了旧城改造容积率测算模型,分析了容积率与利润率之间的具体关系。旧城改造实施人员可据此提出适宜的旧城改造方案。最后,本文以重庆市某旧城改造地块为例,对其容积率进行了重新测算,提出相关规划改造方案。     

融资融券对我国期指市场影响的实证研究

以融资融券对我国期指市场的影响为对象进行实证研究,发现融资融券对期指市场当日成交金额产生负向影响,对期指市场当日持仓量产生正向作用;融资融券交易与期指市场波动性之间不存在长期稳定的协整关系,也不存在确定的线性关系;融资融券交易对期指市场当日成交金额并不存在统计意义上的因果引致关系,当日融券余额与期指市场当日持仓量存在双向因果引致关系,期指市场波动性是融券余额的单向因果引致关系。因此,扩大融资融券标的范围与可供借贷证券池,发展有利于中小投资者参与的、与融资融券交易有关的风险对冲套利金融产品是我国证券市场转型的重要举措。     

The new goods margin in new markets

We analyze the role of the new goods margin in the Baltic countries’ exports and imports growth during the 1995–2008 period. Using the methodology developed in Kehoe and Ruhl (2013), we define the set of least-traded goods as those that account for the lowest 10% of total exports and imports in 1995, and then trace its growth in several markets including the Baltics’ main trade partners, the European Union and Russia. We find that, on average, by 2008 least-traded goods accounted for nearly 50% of total Baltic exports to their main trade partners. Moreover, we find that increases in the share of least-traded exports coincided with the timing of the trade liberalization reforms implemented by the Baltic countries. Least-traded imports also grew at robust rates, but their growth was lower than that of exports, accounting for slightly less than a quarter of total imports, that is, about half of the exports value. Moreover, we find that the shares of least-traded imports from the EU 15 and from Russia started diverging around the time the Baltic countries joined the EU, with the EU 15 share increasing and the Russian one declining. We also find that the Baltics’ share of least-traded exports outpaced that of other economies in Central and Eastern Europe. Finally, exports of new goods from the Baltic countries suffered noticeably during the Global Financial Crisis. After the crisis ended, the restart in new goods exports growth displayed mixed patterns.