• East Asian Economic Review
• /
• v.27 no.1
• /
• pp.33-60
• /
• 2023

This paper analyzes the entire distribution of stock market returns/volatility in five emerging markets (ASEAN5) and figures out the conditional distribution of the CHI_EPU index. The aim is to examine the impact of CHI_EPU on the stock returns/volatility density of ASEAN5 markets. It also examined whether changes in CHI_EPU explain returns at higher or lower points (abnormal returns). This paper models the behaviour of stock returns from March 2011 to June 2018 using a non-parametric conditional density estimation approach. The results indicate that CHI_EPU diminishes stock returns and augments volatility in ASEAN5 markets, except for Malaysia, where it affects stock returns positively. The possible reason for this positive impact is that EPU is not the leading factor reducing Malaysian stock returns; but, other forces, such as dependency on other countries' stock markets and global factors, may have a positive impact on stock returns (Bachmann and Bayer, 2013). Thus, the risk of simultaneous investment in Chinese and ASEAN5 stock markets, except Malaysia, is high. Further, the degree of this influence intensifies at extreme high/low intervals (positive/negative tails). The findings of this study have significant implications for investors, policymakers, market agents, and analysts of ASEAN5.

• Asia-Pacific Journal of Business
• /
• v.14 no.3
• /
• pp.45-66
• /
• 2023

Purpose - This paper examines whether overnight returns and idiosyncratic volatility (IVOL) jointly affects the cross-section of expected stock returns in the Korean stock market. Design/methodology/approach - Constructing 5×5 bivariate monthly portfolios independently sorted on overnight returns and IVOL, this paper tests whether overpricing of stocks with high overnight returns is more pronounced for the stocks that also have high IVOL. In addition, we also investigate whether time-variation in the degree of overpricing for those stocks can be explained by market volatility. Findings - Our results show that stocks having both high overnight returns and high IVOL exhibit strong negative returns in the future. In contrast, we are unable to observe such negative returns for the stocks that have high overnight returns and low IVOL. This suggests that overpricing of stocks with high overnight returns is concentrated for the stocks having high IVOL. Moreover, we also find that the degree to which such stocks are overpriced is negatively related to market volatility. Research implications or Originality - his paper is the first attempt to explore whether degree of overpricing of stocks having high overnight returns is related to IVOL. We also discover time-varying property of overpricing is jointly driven by overnight returns and IVOL. Our results indicate that IVOL might help explain other previously documented stock return anomalies, suggesting interesting topics for future research.

• East Asian mathematical journal
• /
• v.34 no.1
• /
• pp.1-16
• /
• 2018

We study an optimization problem for hyperbolic absolute risk aversion (HARA) utility function under two-factor Heston's stochastic volatility model. It is not possible to obtain an explicit solution because our financial market model is complicated. However, by using asymptotic analysis technique, we find the explicit forms of the approximations of the optimal value function and the optimal strategy for HARA utility function.

• Communications for Statistical Applications and Methods
• /
• v.23 no.1
• /
• pp.21-32
• /
• 2016

We study asymptotic expansion formulae for numerical computation of Greeks (i.e. sensitivity) in finance. Our approach is based on the integration-by-parts formula of the Malliavin calculus. We propose asymptotic expansion of Greeks for a stochastic volatility model using the Greeks formula of the Black-Scholes model. A singular perturbation method is applied to derive asymptotic Greeks formulae. We also provide numerical simulation of our method and compare it to the Monte Carlo finite difference approach.

• Communications of the Korean Mathematical Society
• /
• v.28 no.3
• /
• pp.615-633
• /
• 2013

We use a power series expansion method to get an analytic approximation value for the quanto option price under the Hull and White stochastic volatility model, which turns out to be accurate enough by comparing with the simulation prices using Monte Carlo method.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.6
• /
• pp.1305-1310
• /
• 2010

In this paper, we consider a change point test for stochastic volatility models. By considering the relation between moments of the logarithms of squared returns and the parameters, we construct the cusum test to detect changes of the parameters. We also carry out a simulation study and verify that the proposed test is more powerful than the cusum test proposed by Kokoszka and Leipus (2000).

• Bulletin of the Korean Mathematical Society
• /
• v.59 no.2
• /
• pp.507-528
• /
• 2022

We propose a path integral method to construct a time stepwise local volatility for the stock index market under Dupire's model. Our method is focused on the pricing with the Monte Carlo Method (MCM). We solve the problem of randomness of MCM by applying numerical integration. We reconstruct this task as a matrix equation. Our method provides the analytic Jacobian and Hessian required by the nonlinear optimization solver, resulting in stable and fast calculations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10b
• /
• pp.1858-1863
• /
• 1991

The theory of stock option pricing has, recently, attracted attention of many researchers interested not only in finance but also in statistics and control theory. In this field, the problem of estimating stock return volatility is, above all, of great importance in calculating actual stock option value. In this paper, we assume that the stock market is represented by the stochastic volatility model which is the same as that of Hull and White. Then, we propose an approximation function of option value. It is a type of Black-Sholes option formula in which the first and the second order moments of logarithmic stock value are modified in a special form from the original model. Finally, an algorithm of estimating the parameters of the stochastic volatility model is given, and parameters are estimated by using Nikkei 225 index option data.

• Bulletin of the Korean Mathematical Society
• /
• v.46 no.2
• /
• pp.209-227
• /
• 2009

We examine a unified approach of calculating the closed form solutions of option price under stochastic volatility models using stochastic calculus and the Fourier inversion formula. In particular, we review and derive the option pricing formulas under Heston and correlated Stein-Stein models using a systematic and comprehensive approach which were derived individually earlier. We compare the empirical performances of the two stochastic volatility models and the Black-Scholes model in pricing KOSPI 200 index options.

• Asian Journal of Innovation and Policy
• /
• v.6 no.2
• /
• pp.225-244
• /
• 2017

When evaluating the economic value of technology or business project, we need to consider the period and cost for commercialization. Since the discounted cash flow (DCF) method has limitations in that it can not consider consecutive investment or does not reflect the probabilistic property of commercialization cost, we often take it desirable to apply the concept of real options with key metrics of underlying asset value, commercialization cost, and volatility, while regarding the value of technology and investment as the opportunity value. We at this moment provide more elaborated real options model with the effective region of volatility, which reflects the uncertainty in the option pricing model (OPM).