• The Journal of Information Systems
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• v.30 no.3
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• pp.21-45
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• 2021

Purpose This paper analyzed the impacts of domestic stock market by a global pandemic such as COVID-19. We investigated how the overall pattern of the stock market changed due to the impact of the COVID-19 pandemic. In particular, we analyzed in depth the pattern of stock price, as well, tried to find what factors affect on stock market index(KOSPI) in the healthcare industry due to the COVID-19 pandemic. Design/methodology/approach We built a data warehouse from the databases in various industrial and economic fields to analyze the changes in the KOSPI due to COVID-19, particularly, the changes in the healthcare industry centered on bio-medicine. We collected daily stock price data of the KOSPI centered on the KOSPI-200 about two years before and one year after the outbreak of COVID-19. In addition, we also collected various news related to COVID-19 from the stock market by applying text mining techniques. We designed four experimental data sets to develop decision tree-based prediction models. Findings All prediction models from the four data sets showed the significant predictive power with explainable decision tree models. In addition, we derived significant 10 to 14 decision rules for each prediction model. The experimental results showed that the decision rules were enough to explain the domestic healthcare stock market patterns for before and after COVID-19.

• The Korean Journal of Financial Management
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• v.14 no.1
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• pp.141-169
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• 1997

본 논문은 시장개설 초기 4개월간의 주가지수 선물수익률과 기초자산인 현물(KOSPI 200) 수익률간의 선도-지연효과를 두 개의 모형을 이용하여 실증검증하였다. 첫 번째 모형은 설명 변수로 선물수익률의 시차변수를 사용하고 종속변수로 현물수익률을 사용했다. 두 번째 모형은 설명변수로 선물수익률의 시차변수를 사용하는 것은 첫 번째 모형과 같으나 종속변수로 ARMA모형에서 구한 현물수익률의 오차항(return innovations)을 사용하였다. 또, 여러 시장조건에서 현물수익률과 선물수익률사이의 선도-지연효과가 특정한 양상을 보이는가를 분석하였다. 좋은 정보와 나쁜 정보, 거래량이 많은 경우와 적은 경우, 변동성이 높은 경우와 낮은 경우로 나누어서 선도-지연효과를 살펴보았다. 실증검증의 결과 KOSPI 200 현물수익률은 ARMA(2,3) 모형이 적합하며 선물이 현물을 10분 이내로 선도한다. 하지만 그 관계는 일방적인 것이 아니어서 15분후에는 현물이 선물을 선도하는 피드백(feed-back) 현상이 나타났다. 좋은 정보(good news)에서는 선물이 현물을 5분정도 선도하고 나쁜 정보(bad news)하에서는 선물 선도현상이 약해진다. 보통 정보(morderate news)하에서는 현물이 선물을 10분내로 선도한다. 거래량이 많은 경우와 변동성이 높은 경우에는 선물이 현물을 선도하는 것이 뚜렷하나 거래량이 적은 경우와 변동성이 낮은 경우에는 선물과 현물간에는 특정한 선도-지연현상이 나타나지 않는다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.756-763
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• 2005

본 논문에서는 KOSPI200 지수선물의 분 단위 가격 데이터를 이용하여 거래비용을 고려한 옵션 복제 전략들의 성과를 비교하였다. 비교를 위해 사용한 옵션 복제 전략들은 (1)Black-Scholes 델타(delta) 전략, (2)Black-Scholes 델타 한도 전략, (3)Leland 전략, (4)Whalley-Wilmott 전략이다. 각 전략들은 옵션 복제를 위한 기초자산 거래와 관련된 두 가지 질문에 대한 답을 준다. 첫 번째 질문은 거래 시점에 관한 것으로, '언제 거래할 것인가'이고, 두 번째 질문은 거래량에 관한 것으로, '얼마만큼 거래할 것인가'이다. 본 논문에서는 현실적인 KOSPI200 지수선물 거래수수료(거래금액 대비 0.01%) 환경에서 잔존만기 1년인 유럽형 등가격 콜 옵션을 복제하는 경우를 실험하였다. 실험 결과 Leland 전략을 제외한 나머지 세 전략들의 복제 성과가 상대적으로 뛰어난 것으로 나타났다. 그러나 이들 세 전략들 간에는 복제 성과에 대해 뚜렷한 차이를 발견하기 어려웠다. 한편, 복제 종료 시점에서의 복제 손익에 큰 영향을 미치는 요인은 복제 오차(복제 포트폴리오의 만기 가치와 복제 대상 옵션의 만기 현금흐름의 차이)인 것으로 나타난 반면, 복제를 위한 기초자산 거래비용이 복제 종료 시점에서의 복제 손익에 미치는 영향은 적은 것으로 나타났다.

• The Korean Journal of Applied Statistics
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• v.22 no.6
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• pp.1203-1214
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• 2009

In this paper we introduce the time series clustering methods in the time and frequency domains and discuss the merits or demerits of each method. We analyze 15 daily stock prices of KOSPI 200, and the nonparametric method using the wavelet shows the best clustering results. For the clustering of nonstationary time series using the spectral density, the EMD method remove the trend more effectively than the differencing.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.183-196
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• 2012

The inference for incomplete data such as missing data, truncated distribution and censored data is a phenomenon that occurs frequently in statistics. To solve this problem, Expectation Maximization(EM), Monte Carlo Expectation Maximization(MCEM) and Stochastic Expectation Maximization(SEM) algorithm have been used for a long time; however, they generally assume known distributions. In this paper, we propose the Metropolis-Hastings Expectation Maximization(MHEM) algorithm for unknown distributions. The performance of our proposed algorithm has been investigated on simulated and real dataset, KOSPI 200.

• The Korean Journal of Financial Management
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• v.26 no.2
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• pp.181-201
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• 2009

This study is on the forecasting performance analysis of range volatility estimators(Parkinson, Garman and Klass, and Rogers and Satchell) relative to historical one using two-scale realized volatility estimator as a benchmark. American sub-prime mortgage loan shock to Korean stock markets happened in sample period(January 2, 2006~March 10, 2008), so the structural change somewhere within this period can make a huge influence on the results. Therefore sample was divided into two sub-samples by May 30, 2007 according to Zivot and Andrews unit root test results. As expected, the second sub-sample was much more volatile than the first sub-sample. As a result of forecasting performance analysis, Rogers and Satchell volatility estimator showed the best forecasting performance in the full sample and relatively better forecasting performance than other estimators in sub-samples. Range volatility estimators showed better forecasting performance than historical volatility estimator during the period before the outbreak of structural change(the first sub-sample). On the contrary, the forecasting performance of range volatility estimators couldn't beat that of historical volatility estimator during the period after this event(the second sub-sample). The main culprit of this result seems to be the increment of range volatility caused by that of intraday volatility after structural change.

• Asia-Pacific Journal of Business
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• v.14 no.2
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• pp.33-49
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• 2023

Purpose - The purpose of this study is to examine the option selection and optimal trading of informed traders in KOSPI 200 options market based on the PIN (probability of informed trading) model of Easley et al.(2002). Design/methodology/approach - This study uses TAQ (trade and quote) data provided by Korean Exchanges (KRX) which contains all the bids and trades recorded during the continuous auction trading hours for the KOSPI 200 options between May 2019 and September 2020. Findings - First, there was no difference in the PIN between call and put options in the 2019 data, but the PIN of put options was slightly higher in 2020. Second, regardless of the type of option, the PIN was higher for in-the-money (ITM) options, and the PIN of out-of-the-money (OTM) options was the same as or slightly higher than that of at-the-money (ATM) options. Third, we found that the PIN decreases as trading liquidity increases, and fourth, the PIN increased sharply as the expiration date approached, especially for OTM options, while ITM and ATM options showed relatively weak effects. Fifth, for foreign and institutional investors, the periodicity of orders was observed in milliseconds, especially for foreign investors, where the periodicity of orders was clear and frequent in OTM options. The results suggest that the purpose of option trading varies depending on the moneyness from the perspective of the informed trader.

• Journal of the Korean Data and Information Science Society
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• v.22 no.1
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• pp.37-47
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• 2011

Stock price index option market has various investment strategies that have been developed. Specially, arbitrage strategies are very important to be efficient in option market. The purpose of this study is to improve profit using rough set and Box spread by using past option trading data. Option trading data was based on an actual stock exchange market tick data ranging from 2001 to 2006. Validation process was carried out by transferring the tick data into one-minute intervals. Box spread arbitrage strategies is low risk but low profit. It can be accomplished by back-testing of the existing strategy of the past data and by using rough set, which limit the time line of dealing. This study can make more stable profits with lower risk if control the strategy that can produces a higher profit module compared to that of the same level of risk.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1061-1073
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• 2009

Stock price index option investing is a scientific investment method and various index and investment strategies have been developed. The purpose of this study is to apply the variety of option investment strategies that have been introduced in the market and validate them using past option trading data. Option data was based on an actual stock exchange market tick data ranging from September 2001 to January 2007. Visual Basic is used to propose an option back-testing model. Validation process was carried out by transferring the tick data into ten-minute intervals and empirically analyzed. Furthermore, most option-related strategies have been applied to the model, and the usefulness of each strategies can be easily evaluated. As option investment has high leverage followed by high risks and profit, the optimal option investment strategy should be used according to the market condition at the time to make stable profit with minimum risk.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.48-58
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• 2013

The stock market is constantly changing and sometimes a slump or a sudden rising in stocks happens without any special reason. So the stock market is recognized as a complex system and it is hard to predict the change on stock prices. In this paper we consider the stock market to a network consisting of stocks. We analyzed the dynamics of the Korean stock market network and evaluated the changing of the correlation between shares consisting of the time series data of 137 companies belong to KOSPI200. Our analysis shows that the stock prices tend to plummet when the correlation between stocks is very high. We propose a method for recommending the stock portfolio based on the analysis of the stock market network. To show the effectiveness of the recommended portfolio, we conducted the simulated stock investment and compared the recommended portfolio with the efficient portfolio proposed Markowitz. According to the experiment results, the rate of return of the portfolio is about 10.6% which is about 3.7% and 5.6% higher than the average rate of return of the efficient portfolio and KOSPI200 respectively.