Short-time at-the-money skew and rough fractional volatility

The Black–Scholes implied volatility skew at the money of SPX options is known to obey a power law with respect to the time to maturity. We construct a model of the underlying asset price process which is dynamically consistent to the power law. The volatility process of the model is driven by a fractional Brownian motion with Hurst parameter less than half. The fractional Brownian motion is correlated with a Brownian motion which drives the asset price process. We derive an asymptotic expansion of the implied volatility as the time to maturity tends to zero. For this purpose, we introduce a new approach to validate such an expansion, which enables us to treat more general models than in the literature. The local-stochastic volatility model is treated as well under an essentially minimal regularity condition in order to show such a standard model cannot be dynamically consistent to the power law.     

Hong Kong's growth synchronization with China and the US: A trend and cycle analysis

This paper investigates the synchronization of Hong Kong's economic growth with mainland China and the US. We identify trends of economic growth based on the permanent income hypothesis. Specifically, we first confirm whether real consumption in Hong Kong and mainland China satisfies the permanent income hypothesis, at least in a weak form. We then identify the permanent and transitory components of income of each economy using a simple state-space model. We use structural vector autoregression models to analyze how permanent and transitory shocks originating from mainland China and the US affect the Hong Kong economy, and how such influences evolve over time. Our main findings suggest that transitory shocks from the US remain a major driving force behind Hong Kong's business cycle fluctuations. On the other hand, permanent shocks from mainland China have a larger impact on Hong Kong's trend growth.     

Debt sustainability in emerging market countries: Some policy guidelines from a fan-chart approach

This paper uses a probabilistic approach to simulate the medium-term public debt trajectories of several major emerging market countries. We extend the standard debt sustainability analysis framework so as to more faithfully reproduce these countries’ economic reality in two aspects. First, we allow them to differ in the cyclical stance of their fiscal policy and in their degree of fiscal responsiveness to debt. Second, we explicitly integrate the specific risk premium paid by each country when borrowing in foreign currency. It allows us to evaluate the impact of alternative policies that the government may consider to improve sustainability. The results lead to three policy recommendations: i) a country should consider decreasing its exposure to currency risk only in extreme cases (like Argentina); ii) on the contrary, greater fiscal responsiveness (i.e. stronger fiscal tightening whenever there is a debt increase) could enhance sustainability to a much greater extent; iii) countries with low responsiveness to debt or a poor fiscal consolidation track record should be cautious with countercyclical fiscal policies, as they may trigger an unsustainable debt trajectory in the trough of the economic cycle.     

Basel regulations and banks’ efficiency: The case of the Philippines

Using stochastic frontier analysis, this paper has examined the impact of Basel II on the cost efficiency of Philippine commercial banks from 2001 to 2011. The overall mean cost efficiency estimate is 0.75, indicating substantial inefficiencies in the banks averaging to 25% of total costs. Findings show that higher capital requirement tends to improve the cost efficiency but more powerful supervisors can adversely affect the efficiency of the banks. The other potential correlates that may help explain the efficiency of the banks are risk and asset quality and bank-specific variables. From a policy perspective, this study is informative to policymakers on the general direction in which to proceed with reforms (i.e., maintain higher capital requirements, curtail powerful supervisors, and enhance private monitoring) and in identifying factors that could contribute to banks’ efficiency especially in light of the newly implemented Basel III in the country. In effect, this paper also assesses the readiness of the banks toward the implementation of Basel III.     

Personalized goal-based investing via multi-stage stochastic goal programming

In this paper, we propose a goal-based investment model that is suitable for personalized wealth management. The model only requires a few intuitive inputs such as size of wealth, investment amount, and consumption goals from individual investors. In particular, a priority level can be assigned to each consumption goal and the model provides a holistic solution based on a sequential approach starting with the highest priority. This allows strict prioritization by maximizing the probability of achieving higher priority goals that are not affected by goals with lower priorities. Furthermore, the proposed model is formulated as a linear program that efficiently finds the optimal financial plan. With its simplicity, flexibility, and computational efficiency, the proposed goal-based investment model provides a new framework for automated investment management services.     

Maximizing an equity portfolio excess growth rate: a new form of smart beta strategy?

It has been claimed that, for dynamic investment strategies, the simple act of rebalancing a portfolio can be a source of additional performance, sometimes referred to as the volatility pumping effect or the diversification bonus because volatility and diversification turn out to be key drivers of the portfolio performance. Stochastic portfolio theory suggests that the portfolio excess growth rate, defined as the difference between the portfolio expected growth rate and the weighted-average expected growth rate of the assets in the portfolio, is an important component of this additional performance (see Fernholz [Stochastic Portfolio Theory, 2002 (Springer)]). In this context, one might wonder whether maximizing a portfolio excess growth rate would lead to an improvement in the portfolio performance or risk-adjusted performance. This paper provides a thorough empirical analysis of the maximization of an equity portfolio excess growth rate in a portfolio construction context for individual stocks. In out-of-sample empirical tests conducted on individual stocks from 4 different regions (US, UK, Eurozone and Japan), we find that portfolios that maximize the excess growth rate are characterized by a strong negative exposure to the low volatility factor and a higher than 1 exposure to the market factor, implying that such portfolios are attractive alternatives to competing smart portfolios in markets where the low volatility anomaly does not hold (e.g. in the UK, or in rising interest rate scenarios) or in bull market environments.     

城镇就业市场上劳动力工资扭曲程度测度

本文利用CHIPS2007数据库，基于随机前沿模型对我国城镇就业市场上劳动力的工资扭曲程度进行测度。研究结果表明：（1）在城镇就业市场上，由于工资扭曲现象的存在，劳动力实际获得的工资要比他们的边际生产率低45％～60％；（2）已婚、子女个数较少、本地、拥有失业保险、男性、大中型企业的劳动力工资扭曲程度要低于未婚、子女个数较多、外来、没有失业保险、女性、小型企业的劳动力；（3）中低工资水平的劳动力工资扭曲程度要比高工资水平的劳动力严重，且中低工资水平劳动力工资扭曲程度的方差更大。由此，本文提出推进就业市场的市场化改革，完善就业市场信息网络，从而减轻劳动力工资扭曲程度。     

Measuring systemic risk with regime switching in tails

This paper motivates the importance of modeling nonlinearities in measuring systemic risk. I capitalize this motivation by generalizing the CoVaR approach proposed by Adrian and Brunnermeier (2016) to allow it switching between a high and a normal risk regime filtered from data.. Considering the U.S. large bank holding companies (BHCs), this paper shows that modeling regime changes in tails is capable of capturing both amplification and mean-reversion effects of an adverse shock to a bank's balance sheet on the banking system. Using the Kolmogorov–Smirnov test statistics with and without bootstrapping, I perform the significance test to identify systemically important financial institutions (SIFIs), and the stochastic dominance test to rank the identified SIFIs. The stochastic dominance test raises the concern that the CoVaR measure underestimates systemic risk contributions for SIFIs but overestimates for non-SIFIs. Finally, applying the BHCs' characteristics and housing market price to forecast the regime-switching systemic risk out-of-sample, I obtain from 4- and 8-quarter-ahead horizons a desirable countercyclical, forward-looking measure of systemic risk.     

汇改、人民币国际化与汇率定价权 —基于双边随机前沿模型的实证研究

本文通过构建人民币外汇市场中关于人民币汇率定价权力的双边随机前沿模型, 分析了中外定价权差异对于人民币汇率的影响。实证研究表明,中国在人民币外汇市场上较外 部经济体具有更强的定价权力,近期的汇率贬值并非政府操作行为而是市场均衡结果;人民币 国际化和汇率市场化进程可以矫正偏离。本文的政策建议为：（1）继续推进人民币国际化和 汇改市场化进程。（2）进一步提高外部经济体参与人民币外汇市场交易的深度和广度。