• 한국컴퓨터정보학회논문지
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• 제21권6호
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• pp.9-19
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• 2016

In finance literature, stock liquidity showing how stocks can be cashed out in the market has received rich attentions from both academicians and practitioners. The reasons are plenty. First, it is known that stock liquidity affects significantly asset pricing. Second, macroeconomic announcements influence liquidity in the stock market. Therefore, stock liquidity itself affects investors' decision and managers' decision as well. Though there exist a great deal of literature about stock liquidity in finance literature, it is quite clear that there are no studies attempting to investigate the stock liquidity issue as one of decision making problems. In finance literature, most of stock liquidity studies had dealt with limited views such as how much it influences stock price, which variables are associated with describing the stock liquidity significantly, etc. However, this paper posits that stock liquidity issue may become a serious decision-making problem, and then be handled by using data mining techniques to estimate its future extent with statistical validity. In this sense, we collected financial data set from a number of manufacturing companies listed in KRX (Korea Exchange) during the period of 2010 to 2013. The reason why we selected dataset from 2010 was to avoid the after-shocks of financial crisis that occurred in 2008. We used Fn-GuidPro system to gather total 5,700 financial data set. Stock liquidity measure was computed by the procedures proposed by Amihud (2002) which is known to show best metrics for showing relationship with daily return. We applied five data mining techniques (or classifiers) such as Bayesian network, support vector machine (SVM), decision tree, neural network, and ensemble method. Bayesian networks include GBN (General Bayesian Network), NBN (Naive BN), TAN (Tree Augmented NBN). Decision tree uses CART and C4.5. Regression result was used as a benchmarking performance. Ensemble method uses two types-integration of two classifiers, and three classifiers. Ensemble method is based on voting for the sake of integrating classifiers. Among the single classifiers, CART showed best performance with 48.2%, compared with 37.18% by regression. Among the ensemble methods, the result from integrating TAN, CART, and SVM was best with 49.25%. Through the additional analysis in individual industries, those relatively stabilized industries like electronic appliances, wholesale & retailing, woods, leather-bags-shoes showed better performance over 50%.

• 아태비즈니스연구
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• 제11권4호
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• pp.317-332
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• 2020

Purpose - This study examines the information effect and trading behavior of investors for the 430 stock split data from January 2004 to June 2018 in the Korean stock market. Design/methodology/approach - The stock split samples are classified into two groups by split ratio as well as three groups by price level prior to split. We also investigate the trading behavior of investors categorized by institutional versus individual investors. Findings - First, we find a significantly positive information effect on the announcement day. In particular, the information effect is more distinct in the group of larger split ratio and higher price level of stocks. Second, we find a huge increase in turnover following the stock splits, which mainly results from the trading by individual investors. Also, the increase in turnover by individual investors is evident in the group of larger split ratio and higher price level of stocks. Third, the stock splits have a negative impact on the long-term stock performance. The negative buy-and-hold abnormal return(BHAR) makes no difference in the groups by split ratio as well as price level of stocks. Lastly, we find individual investors tend to buy splitted stocks, which exhibit the long-term under-performance. Research implications or Originality - The results in this paper suggest that the liquidity hypothesis is not supported in the Korean stock splits. In addition, we observe that individual investors are exposed to losses due to their unfavorable trading behavior following the stock split.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.99-110
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• 2021

This study aims to examine empirically the industry and economic fundamental factors that affect the stock prices of the leading palm oil company in Indonesia. The dynamics of stock price are analyzed using the autoregressive distribution lag (ARDL) model both for symmetric and asymmetric effects. The data used in this study are monthly data for the period from 2008:01 to 2020:03. In the long run, the company stock price moves in line with the competitor company stock price at the current time. The palm oil price has a positive effect on the stock price. Meanwhile, inflation negatively affects the stock price in the short run. The estimated equilibrium correction coefficient indicates a reasonably quick correction of the distortion of the stock price equilibrium in monthly dynamics. However, fundamental factors have asymmetric effects, especially the response of stock price when these factors decrease rather than increase in the short run. Stock prices that are responsive to declines in fundamental performance should be of particular concern to both investors and management in their strategic decision making. The results of this study will contribute to the enrichment of literature related to stock prices from the viewpoint of economic analysis on firm-level data.

• 한국경영과학회지
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• 제38권4호
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• pp.35-52
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• 2013

Markowitz's portfolio selection model is used to construct an optimal portfolio which has minimum variance, while satisfying a minimum required expected return. The model uses estimators based on analysis of historical data to estimate the returns, standard deviations, and correlation coefficients of individual stocks being considered for investment. However, due to the inaccuracies involved in estimations, the true optimality of a portfolio constructed using the model is questionable. To investigate the effect of estimation inaccuracy on actual portfolio performance, we study the changes in a portfolio's realized return and standard deviation as the accuracy of the estimations for each stock's return, standard deviation, and correlation coefficient is increased. Furthermore, we empirically analyze the portfolio's performance by comparing it with the performance of active mutual funds that are being traded in the Korean stock market and the KOSPI benchmark index, in terms of portfolio returns, standard deviations of returns, and Sharpe ratios. Our results suggest that, among the three input parameters, the accuracy of the estimated returns of individual stocks has the largest effect on performance, while the accuracy of the estimates of the standard deviation of each stock's returns and the correlation coefficient between different stocks have smaller effects. In addition, it is shown that even a small increase in the accuracy of the estimated return of individual stocks improves the portfolio's performance substantially, suggesting that Markowitz's model can be more effectively applied in real-life investments with just an incremental effort to increase estimation accuracy.

• 아태비즈니스연구
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• 제14권4호
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• pp.431-444
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• 2023

Purpose - This study applies the traditional Structure-Conduct-Performance (SCP) model from industrial organization theory to investigate the relationship between market structure and performance in China's banking industry. Design/methodology/approach - For analysis, financial data from the People's Bank of China's "China Financial Stability Report" and financial reports of 6 state-owned banks and 11 joint-stock banks for the period 2010 to 2021 were collected to create a balanced panel dataset. The study employs panel fixed-effects regression analysis to assess the impact of changes in market structure and ownership structure on performance variables including return on asset, profitability, costs, and non-performing loan ratios. Findings - Empirical findings highlight significant differences in the effects of market structure between state-owned and joint-stock banks. Notably, increased market competition positively correlates with higher profits for state-owned banks and with lower costs for joint-stock banks. Research implications or Originality - State-owned banks demonstrate larger scale and stability, yet they struggle to respond effectively to market shifts. Conversely, joint-stock banks face challenges in raising profitability against competitive pressures. Additionally, the study emphasizes the importance for Chinese banks to strengthen risk management due to the increase of non-performing loans with competition. The results provide insights into reform policies for Chinese banks regarding the involvement of private sector in the context of market liberalization process in China.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권11호
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• pp.625-631
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• 2017

과거부터 현재까지 주식시장에 대한 주가 변동 예측은 풀리지 않는 난제이다. 주가를 과학적으로 예측하기 위해 다양한 시도 및 연구들이 있어왔지만, 아직까지 정확한 미래를 예측하는 것은 불가능하다. 하지만, 주가 예측은 경제, 수학, 물리 그리고 전산학 등 여러 관련 분야에서 오랜 관심의 대상이 되어왔다. 본 논문에서는 최근 각광 받고 있는 딥러닝(Deep-Learning)을 이용하여 주가의 변동패턴을 학습하고 미래를 예측하고자한다. 본 연구에서는 오픈소스 딥러닝 프레임워크인 텐서플로우를 이용하여 총 3가지 학습 모델을 제시하였으며, 각 학습모델은 각기 다른 입력 피쳐들을 받아들여 학습을 진행한다. 입력 피쳐는 이전 연구에서 사용한 단순 가격 데이터를 확장해 입력 피쳐 개수를 증가시켜가며 실험을 하였다. 세 가지 예측 모델의 학습 성능을 측정했으며, 이를 통해 가격-기반 입력 피쳐에 따라 달라지는 예측 모델의 성능 변화 비교 분석하여 가격-기반 입력 피쳐가 주가예측에 미치는 영향을 평가하였다.

• 산업경영시스템학회지
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• 제38권3호
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• pp.8-13
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• 2015

One of the most usual indicators to measure the performance of any inventory policy is the mean physical stock. In general, when estimating the mean physical stock in periodic review inventory systems, approximate approaches are often utilized by practitioners and researchers. The mean physical stock is generally calculated by a simple approximation. Still these simple methods are frequently used to analyze various single stockpoint and multi-echelon inventory systems. However, such a simple approximation can be very inaccurate. This is particularly true for low service levels. Even though exact methods to calculate the mean physical stock have been derived, they are available for specific cases only and computationally not very efficient, and therefore less useful in practice. In literature, approximate approaches, such as the simple, the linear, and Simpson approximations, were derived for the periodic review inventory systems that allow backorders. This paper modifies the approximate approaches for the lost sales case and evaluates the modified approximate approaches. Through computational experiments, average (and maximum) percentage deviations of mean physical stock between the exact method and the modified approximations are compared in the periodic review inventory system with lost sales. The same comparison between the modified and the original approximations are also conducted, in order to examine the performance of modified approximations. The results show that all modified approximations perform well for high service levels, but also that the performance may deteriorate fast with decreasing service level. The modified Simpson approximation is clearly better. In addition, the comparison between the modified and the original approximations in the periodic review inventory system with lost sales shows that the modified approximation outperforms the original approximation.

• 한국정보시스템학회지:정보시스템연구
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• 제32권1호
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• pp.179-199
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• 2023

Purpose This study builds a prediction model to find stocks that can reach intrinsic value among KOSPI and KOSDAQ-listed companies to improve the stability and profitability of the stock investment. And investment simulations are conducted to verify whether stock investment performance is improved by comparing the prediction model, random stock selection, and the market indexes. Design/methodology/approach Value investment theory and machine learning techniques are applied to build the model. Various experiments find conditions such as the algorithm with the best predictive performance, learning period, and intrinsic value-reaching period. This study selects stocks through the prediction model learned with inventive variables, does not limit the holding period after buying to reach the intrinsic value of the stocks, and targets all KOSPI and KOSDAQ companies. The stock and financial data are collected for 21 years (2001-2021). Findings As a result of the experiment, using the random forest technique, the prediction model's performance was the best with one year of learning period and within one year of the intrinsic value reaching period. As a result of the investment simulation, the cumulative return of the prediction model was up to 1.68 times higher than the random stock selection and 17 times higher than the KOSPI index. The usefulness of the prediction model was confirmed in that the number of intrinsic values reaching the predicted stock was up to 70% higher than the random selection.

• Asian Journal of Business Environment
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• 제10권1호
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• pp.19-28
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• 2020

Purpose: This research aims to investigate the impact of corporate integrity on stock price crash risk. Research design, data, and methodology: Taking 1419 firms listed in Shenzhen Stock Exchange in China as a sample, this paper empirically analyzed the relationship between corporate integrity and stock price crash risk. The main integrity data was hand-collected from Shenzhen Stock Exchange Website. Other financial data was collected from CSMAR Database. Results: Findings show that corporate integrity can significantly decrease stock price crash risk. After changing the selection of samples, model estimation methods and the proxy variable of stock price crash risk, the conclusion is still valid. Further research shows that the relationship between corporate integrity and stock price crash risk is only found in firms with weak internal control and firms in poor legal system areas. Conclusions: Results of the study suggest that corporate integrity has a significant influence on behaviors of managers. Business ethics reduces the likelihood of managers to overstate financial performance and hide bad news, which leads to the low likelihood of future stock price crashes. Meanwhile, corporate integrity can supplement internal control and legal system in decreasing stock price crash risks.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.132-139
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• 2019

We address the problem about forecasting the direction of stock price movement in the Korea market. Recently, the deep neural network is popularly applied in this area of research. In deep neural network systems, proper parameter initialization reduces training time and improves the performance of the model. Therefore, in our study, we propose a novel parameter initialization technique and apply this technique for the stock price movement prediction model. Specifically, we design a framework which consists of two models: a base model and a main prediction model. The base model constructed with LSTM is trained by using the large data which is generated by a large amount of the stock data to achieve optimal parameters. The main prediction model with the same architecture as the base model uses the optimal parameter initialization. Thus, the main prediction model is trained by only using the data of the given stock. Moreover, the stock price movements can be affected by other related information in the stock market. For this reason, we conducted our research with two types of inputs. The first type is the stock features, and the second type is a combination of the stock features and the Korea Composite Stock Price Index (KOSPI) features. Empirical results conducted on the top five stocks in the KOSPI list in terms of market capitalization indicate that our approaches achieve better predictive accuracy and F1-score comparing to other baseline models.