COVID-19, stock market and sectoral contagion in US: a time-frequency analysis

We assess the conditional relationship in the time-frequency domain between the return on S&P 500 and confirmed cases and deaths by COVID-19 in Hubei, China, countries with record deaths and the world, for the period from January 29 to June 30, 2020. Methodologically, we follow Aguiar-Conraria et al. (2018), by using partial coherencies, phase-difference diagrams, and gains. We also perform a parametric test for Granger-causality in quantiles developed by Troster (2018). We find that short-term cycles of deaths in Italy in the first days of March, and soon afterwards, cycles of deaths in the world are able to lead out-of-phase US stock market. We find that low frequency cycles of the US market index in the first half of April are useful to anticipate in an anti-phasic way the cycles of deaths in the US. We also explore sectoral contagion, based on dissimilarities, Granger causality and partial coherencies between S&P sector indices. Our findings, such as the strategic role of the energy sector, which first reacted to the pandemic, or the evidence about predictability of the Telecom cycles, are useful to tell the history of the pass-through of this recent health crises across the sectors of the US economy.     

A Dynamic Analysis of Fixed- and Adjustable-Rate Mortgage Terminations

This paper provides a side-by-side comparison of loan-level statistical models for fixed- and adjustable-rate mortgages. Multinomial logit models for quarterly conditional probabilities of default and prepayment are estimated. We find that the estimated impacts of embedded option values for prepayment and default are generally quite similar across both FRM and ARM loans, providing additional empirical support for the basic predictions of the options theory. We also find that differences in estimates of conditional probabilities of prepayment and default associated with mortgage age, origination period, original LTV, and relative loan size, indicate the continued significance of these other economic and demographic factors for empirical models of mortgage terminations.     

The Random Walk Hypothesis in the Emerging Indian Stock Market

This paper examines the random walk hypothesis in the emerging Indian stock market using daily data on individual stocks. The statistical evidence in this paper rejects the random walk hypothesis. The results suggest that daily returns earned by individual stocks and by an equally weighted portfolio show significant non–linear dependence and persistent volatility effects. The non–linear dependence takes the form of ARCH–type conditional heteroskedasticity and does not appear to be caused by nonstationarity of underlying economic variables. Though conditional volatility is time varying, it does not explain expected returns.     

我国地区经济增长收敛的动态变化:1978—2017年

改革开放40年来，我国地区经济增长收敛现象较为明显。地区人均GDP增长不仅持续上升，而且水平差距也在不断缩小，存在条件收敛现象，并且东部和沿海地区经济增长的"俱乐部收敛"现象显著。进入20世纪90年代后，增长收敛趋势愈发突出，2008年国际金融危机也未影响增长收敛的发展态势。未来要继续坚持改革开放，补上各地制度和要素的短板，积极培育和发展有利于地区人均GDP增长收敛现象产生的一系列基础性因素，以实现区域更加协调发展。     

Conditional mean functions of non-linear models of US output

We compare a number of models of post War US output growth in terms of the degree and pattern of non-linearity they impart to the conditional mean, where we condition on either the previous period's growth rate, or the previous two periods' growth rates. The conditional means are estimated non-parametrically using a nearest-neighbour technique on data simulated from the models. In this way, we condense the complex, dynamic, responses that may be present in to graphical displays of the implied conditional mean. First version received: Feb. 1999/Final version received: June 2001     

Portfolio Optimization under Lower Partial Risk Measures

Portfolio management using lower partial risk (downside risk) measures is attracting more attention of practitioners in recent years. The purpose of this paper is to review important characteristics of these riskmeasures and conduct simulation using four alternative measures, lower semi-variance, lower semi-absolute deviation, first order below targetrisk and conditional value-at-risk.We will show that these risk measures are useful to control downside risk whenthe distribution of assets is non-symmetric. Further, we will propose a computational scheme to resolve the difficultyassociated with solving a large dense linear programming problems resulting from these models. We will demonstrate that this method can in fact solve problems consisting of10⁴ assets and 10⁵ scenarios within a practical amount of CPU time.     

经济增长在险水平、条件波动性与经济增长态势研究

经济增长在险水平（GaR）和条件标准差（CSD）能够有效地度量国家经济风险波动的单向性和双向性。利用动态时窗和条件异方差模型，我们发现我国国家经济风险与经济周期波动密切相关，目前的国家风险状态已经体现出明显的稳定性。利用协整关系检验，我们发现我国国家经济风险与经济增长水平之间存在正相关的长期均衡关系，因此采取积极经济政策的“反周期”干预，所诱发的适度经济波动将有且经济快速稳定增长。     

A Closer Look at the Relation between GARCH and Stochastic Autoregressive Volatility

We show that, for three common SARV models, fitting a minimummean square linear filter is equivalent to fitting a GARCH model.This suggests that GARCH models may be useful for filtering,forecasting, and parameter estimation in stochastic volatilitysettings. To investigate, we use simulations to evaluate howthe three SARV models and their associated GARCH filters performunder controlled conditions and then we use daily currency andequity index returns to evaluate how the models perform in arisk management application. Although the GARCH models produceless precise forecasts than the SARV models in the simulations,it is not clear that the performance differences are large enoughto be economically meaningful. Consistent with this view, wefind that the GARCH and SARV models perform comparably in testsof conditional value-at-risk estimates using the actual data.     

Credit Events and the Valuation of Credit Derivatives of Basket Type

Thispaper provides a simple model for valuing a credit derivativewhose payoff depends on the identity (or identities) of the first(or first two) to occur of a given list of credit events, suchas defaults. The joint survival probability of occurrence timesof credit events is formulated in terms of stochastic intensityprocesses under the assumption of conditional independence. Basedon the joint survival probability, we can easily obtain the pricingformulas of such credit derivatives under the risk-neutral valuationframework. When the default intensity processes follow the extendedVasicek model, closed-form solutions of the pricing formulasare given.     

基于多视角的我国东北三省工业产业结构趋同问题研究

产业结构调整是加快经济发展的核心问题,是经济高速增长的基本推动力量。因此深入研究地区产业结构趋同问题,对于地区产业结构调整以及产业结构高级化发展具有重要意义。本文利用东北三省合并后23个工业产业2001～2014年的工业总产值数据,通过产业结构相似系数、区位熵以及β趋同系数多角度分析东北三省工业产业结构趋同问题。从发展方向看,我国东北三省合并后23个工业产业相似系数最高的是辽宁和黑龙江省,最低的是吉林和黑龙江省,从专业化水平及总量和发展速度关系看,东北三省工业产业在农副食品加工业、交通运输和通用设备制造业形成了区域优势,但在低附加值、产业链低端的开采业以及劳动密集型产业上还存在不同程度趋同,并提出东北三省工业产业在转型升级中应当重点发展高加工度、高附加值等产业,避免产业间的低端雷同的政策建议。