疫情防控常态化下的世界经济战略走向

新冠疫情的出现冲击了世界经济,从经济全球化和全球经济治理体系两个维度分析疫情对世界经济的影响以及世界经济未来走向,研究发现:(1)新冠疫情通过影响全球价值链、贸易投资和就业环境阻碍经济全球化进程,中美矛盾升级、原有治理体系规则未与时俱进和激进政策的不确定性对全球经济治理体系提出新的挑战;(2)新冠疫情强化了世界各国对人类命运共同体的认识,将人类命运共同体融入全球治理体系将是未来治理的重要趋势;(3)新冠疫情可能会使世界经济格局出现新的变化,而中国在此次疫情中高效率的抗疫举措将进一步提升自身在世界经济格局中的地位和参与度。     

Market impact: a systematic study of the high frequency options market

This paper deals with a fundamental subject that has seldom been addressed in recent years, that of market impact in the options market. Our analysis is based on a proprietary database of metaorders—large orders that are split into smaller pieces before being sent to the market—on one of the main Asian markets. In line with our previous work on the equity market [Said, E., Bel Hadj Ayed, A., Husson, A. and Abergel, F., Market impact: A systematic study of limit orders. Mark. Microstruct. Liq., 2018, 3(3&4), 1850008.], we propose an algorithmic approach to identify metaorders, based on some implied volatility parameters, the at the money forward volatility and at the money forward skew. In both cases, we obtain results similar to the now well-understood equity market: Square-Root Law, Fair Pricing Condition and Market Impact Dynamics.     

Asymmetric information consolidation and price discovery: Inferring bad news from insider sales

Due to the paucity of sources of negative firm‐specific information, US capital markets have more difficulty identifying and incorporating bad news into stock prices than they do good news. Even though insider selling is a potentially important proxy for undisclosed bad news, researchers have difficulty ex ante identifying information‐based sales due to an inability to separate liquidity‐motivated from information‐based insider trades. We hypothesize that when insiders in multiple firms sell shares of one firm in which they are insiders and at the same time buy shares of other insider portfolio firms, the sale is more likely to be information‐based, since the proceeds are reinvested. Conversely, when an insider sells one firm without purchasing others or sells multiple insider firms the sale is likely liquidity‐motivated. We find that insider sales identified as information‐based using this algorithm are followed by significant negative abnormal returns. Information‐based sales are also more likely to be associated with delistings, earnings declines and earnings restatements. Analysts are also more likely to revise their earnings forecasts downwards for these firms. It is thus possible to ex ante identify insider sales with information content. Our results will be of interest to investors and also to regulators designing insider trading rules.     

Parking futures: Preparing European cities for the advent of automated vehicles

The introduction of automated vehicles (AVs) is a virtual certainty. Much less certain is the timing of their introduction and how rapid the transition to full automation will be. Various governments are already working to facilitate this shift by, for example, amending and elaborating regulations to support the introduction of AVs, or supporting tests in different urban environments. Meanwhile, urban and regional planners and decision-makers are still grappling with the uncertainties and differing opinions about the possible impacts of AVs on land-use changes and location choices, particularly in relation to the space available for vehicles, both moving (i.e. roadspace) and stationary (i.e. parking space). This paper uses a backcasting approach to identify critical policy decisions and measures to be taken before the implementation of AVs, so as to achieve a more desirable, attractive and high-quality city. These policy measures primarily relate to the reuse and reallocation of parking and roadspace. Two strategic decisions are found to be essential to meet the major goals of sustainable and liveable cities: a clear commitment to a shared mobility and the delimitation of Core Attractive Mixed-use Spaces (CAMS). In order to deliver these desired urbanisation patterns, a set of three policy paths, involving eight policy packages, is proposed for the next 20–30 years. This article provides urban and regional decision-makers with examples of interventions that can be implemented beyond and during the implementation of AVs.     

The maturity effect of stock index futures: Speculation or carry arbitrage?

Using the implementation of trading restrictions on CSI 300 index futures market as a quasi-natural experiment, this paper examines the maturity effect of stock index futures and its determinants. The results show that the maturity effect changes from weakly positive to significantly negative after trading restrictions are implemented. We find that the change in the maturity effect is rooted in the speculative effect, which is measured by the time pattern of price sensitivity to information, while there is a lack of support for the carry arbitrage effect on the maturity effect of index futures. Our findings provide an opportunity to better understand volatility dynamics in the equity futures market.     

乡村旅游开发下农户生计适应变化与影响机理研究*——以延安市乡村旅游为例

［目的］以延安市3个典型乡村旅游地为例，结合可持续生计分析框架和适应性理论，分析农户在乡村旅游扰动下的适应策略与适应模式，定量测度不同适应模式农户的适应结果。厘清农户未来生计策略选择的影响因素及其机制，提出促进农户及乡村旅游地可持续发展的对策。［方法］通过参与性农户评估法及二元回归分析法分析影响农户未来生计策略选择的因素。［结果］（1）旅游开发造成案例地农户自然资本丧失，失地农户由务农或务工为主的单一适应方式向兼业型与非农型转变，分化为4种不同类型的农户，且各类农户在各描述指标方面差异显著。（2）农户的生计资本衡量3个社区旅游开发后的适应结果，生计资本普遍较低且内部各维度差异明显。对比4类农户适应结果可得：复合生计型>务工主导型>旅游服务型>社会保障型。（3）通过二元逻辑回归模型深入解释当下适应结果对农户未来生计策略选择的影响，物质资本、金融资本和社会资本均影响农户选择意愿，其中可借款人数是最关键的影响变量。［结论］农户在旅游开发背景下生计动态适应的影响机制为旅游开发及基于此补偿制度是农户现在生计适应活动的外部起因，按照适应类型以及收入比重，分化为4种模式农户； 现行生计适应策略使农户适应结果迥异，生计资本的储量和结构差异显著，这种差异是农户未来生计选择的直接动因； 3个社区不同类型的旅游开发模式是农户未来生计策略选择分异的推动力量。     

INDIFFERENCE PRICES AND IMPLIED VOLATILITIES

We consider a general local‐stochastic volatility model and an investor with exponential utility. For a European‐style contingent claim, whose payoff may depend on either a traded or nontraded asset, we derive an explicit approximation for both the buyer's and seller's indifference prices. For European calls on a traded asset, we translate indifference prices into an explicit approximation of the buyer's and seller's implied volatility surfaces. For European claims on a nontraded asset, we establish rigorous error bounds for the indifference price approximation. Finally, we implement our indifference price and implied volatility approximations in two examples.     

Semistatic hedging and pricing American floating strike lookback options

We price an American floating strike lookback option under the Black–Scholes model with a hypothetic static hedging portfolio (HSHP) composed of nontradable European options. Our approach is more efficient than the tree methods because recalculating the option prices is much quicker. Applying put–call duality to an HSHP yields a tradable semistatic hedging portfolio (SSHP). Numerical results indicate that an SSHP has better hedging performance than a delta-hedged portfolio. Finally, we investigate the model risk for SSHP under a stochastic volatility assumption and find that the model risk is related to the correlation between asset price and volatility.     

Option pricing based on hybrid GARCH-type models with improved ensemble empirical mode decomposition

The exploration of option pricing is of great significance to risk management and investments. One important challenge to existing research is how to describe the underlying asset price process and fluctuation features accurately. Considering the benefits of ensemble empirical mode decomposition (EEMD) in depicting the fluctuation features of financial time series, we construct an option pricing model based on the new hybrid generalized autoregressive conditional heteroskedastic (hybrid GARCH)-type functions with improved EEMD by decomposing the original return series into the high frequency, low frequency and trend terms. Using the locally risk-neutral valuation relationship (LRNVR), we obtain an equivalent martingale measure and option prices with different maturities based on Monte Carlo simulations. The empirical results indicate that this novel model can substantially capture volatility features and it performs much better than the M-GARCH and Black–Scholes models. In particular, the decomposition is consistently helpful in reducing option pricing errors, thereby proving the innovativeness and effectiveness of the hybrid GARCH option pricing model.     

土地整治对中国粮食产出稳定性的贡献

研究目的:研究土地整治对粮食产出稳定性的贡献,为制定合理高效的土地整治政策,促进粮食增产稳产提供依据。研究方法:采用H-P滤波法实证分析中国粮食产量的波动性及增长趋势,然后基于C-D生产函数,分别建立趋势产量和波动强度面板回归模型,分析土地整治对粮食产出稳定性的影响。研究结果:(1)粮食作物播种面积、农业机械总动力、农用化肥施用量均对粮食长期趋势产生不同程度促进作用;农业劳动力对主产区粮食长期趋势影响显著为负,对非主产区却有正向影响。(2)土地整治面积和单位面积投资额均降低了全国及主产区粮食产量的波动程度,土地整治规模在全国和主产区的影响系数分别为-1.4162和-2.2215;单位土地整治面积投资额在全国和主产区的影响系数分别为-0.7589和-1.3509。(3)土地整治新增耕地面积对全国和主产区的粮食产量波动强度影响为正,影响系数分别为0.8018和1.3931。可能是通过土地整治新增的耕地质量较低,产出不高,导致了粮食产量波动。土地整治投入在非主产区均表现为不显著。研究结论:应继续推进尤其是主产区的土地整治项目实施,加大土地整治投资强度,建立长期稳定的投入机制,合理使用整治资金,注重提高新增耕地质量和综合生产能力,同时将土地整治投入和管理机制与农业生产系统运行机制、自然因素等有效结合,并制定差别化区域政策,以保障粮食增产稳产和区域协调发展。