• The Journal of Asian Finance, Economics and Business
• /
• 제7권7호
• /
• pp.463-474
• /
• 2020

This study aims to investigate the impact of COVID-19 pandemic on the stock markets of sixteen countries. Pooled OLS regression, conventional t-test and Mann-Whitney test are used to estimate the results of the study. We construct a weekly panel data of COVID-19 new cases and stock returns. Pooled OLS estimation result shows that the growth rate of weekly new cases of COVID-19 negatively predicts the return in stock market. Next, the returns on leading stock indices of these countries during the COVID-19 outbreak period are compared with returns during the non-COVID period. We use a t-test and Mann-Whitney test to compare the returns. The results reveal that investors in these countries do not react to the media news of COVID-19 at the early stage of the pandemic. However, once the human-to-human transmissibility had been confirmed, all of the stock market indices negatively reacted to the news in the short- and long-event window. Interestingly, we noticed that the Shanghai Composite Index, which was severely affected during the short-event window, bounced back during the long-event window. This indicates that the Chinese government's drastic measures to contain the spread of the pandemic regained the confidence of investors in the Shanghai Stock Market.

• 한국정보시스템학회지:정보시스템연구
• /
• 제26권3호
• /
• pp.63-90
• /
• 2017

Purpose This study proposes a novel system trading model using case-based reasoning (CBR) based on absolute similarity threshold. The proposed model is designed to optimize the absolute similarity threshold, feature selection, and instance selection of CBR by using genetic algorithm (GA). With these mechanisms, it enables us to yield higher returns from stock market trading. Design/Methodology/Approach The proposed CBR model uses the absolute similarity threshold varying from 0 to 1, which serves as a criterion for selecting appropriate neighbors in the nearest neighbor (NN) algorithm. Since it determines the nearest neighbors on an absolute basis, it fails to select the appropriate neighbors from time to time. In system trading, it is interpreted as the signal of 'hold'. That is, the system trading model proposed in this study makes trading decisions such as 'buy' or 'sell' only if the model produces a clear signal for stock market prediction. Also, in order to improve the prediction accuracy and the rate of return, the proposed model adopts optimal feature selection and instance selection, which are known to be very effective in enhancing the performance of CBR. To validate the usefulness of the proposed model, we applied it to the index trading of KOSPI200 from 2009 to 2016. Findings Experimental results showed that the proposed model with optimal feature or instance selection could yield higher returns compared to the benchmark as well as the various comparison models (including logistic regression, multiple discriminant analysis, artificial neural network, support vector machine, and traditional CBR). In particular, the proposed model with optimal instance selection showed the best rate of return among all the models. This implies that the application of CBR with the absolute similarity threshold as well as the optimal instance selection may be effective in system trading from the perspective of returns.

• 디지털융복합연구
• /
• 제14권10호
• /
• pp.107-117
• /
• 2016

본 연구는 유가증권시장의 제조업을 대상으로 재무정보의 효율성이 기업가치에 미치는 영향에 대해 정보가 반영되는 시기를 중심으로 검증하고자 하였다. 이를 위해 재무제표 공시를 기준으로 분석기간을 당해(t)년도, 재무제표 공시 전 90일, 차기년도(t+1)로 구분하였다. 실증분석에 사용된 재무변수는 수익성, 성장성, 안정성, 활동성 및 시장가치 비율이며 재무정보가 분석기간 동안의 주식수익률에 미치는 영향을 단계적 회귀분석(stepwise regression)을 이용해 검증하였다. 실증분석 결과, 성장성과 수익성에 관한 정보는 당기의 주식수익률에 반영되는데 비해 안정성과 활동성에 관한 정보는 차기의 주식수익률에 정보를 반영하고 있는 것으로 나타났다. 총자산증가율은 당기 및 차기의 주식수익률에 부(-)의 유의적인 영향을 주는 것으로 나타났으며, 이는 재무정보가 산출된 동기간에 정보가 반영될 뿐만 아니라 차기에도 지속적으로 정보를 반영하는 것으로 판단된다. 본 연구는 재무정보의 성격에 따라 기업가치에 반영되는 시기가 달라지는 것을 발견하였다.

• 산업경영시스템학회지
• /
• 제42권1호
• /
• pp.137-142
• /
• 2019

There are two methods for evaluating two or more mutually exclusive projects. One is a total investment approach and the other is an incremental investment approach. The former can rank projects by the criterion of the net present value, but the latter can't do it. An incremental investment approach is only possible when all pairwise alternatives are compared. Thus an incremental investment approach is superior in ranking them over an incremental investment approach. To do so, a principle of comparison must be established. Comparisons of profitability are reasonable when operating the same amount of investment over the same period of time. One principle is that all projects are invested in the largest of the projects. Another principle is that all projects are invested during the longest project life of the projects. In this paper, even if the principle is followed, it will be shown that the external rate of return fails to rank them. However, the productive rate of return criterion would prove to be able to rank them like the net present value standard, provided that the principle of comparison is kept. In addition, rate of returns can be assessed so that all mutually exclusive projects can be compared at once, such as on the criterion of the net present value. That is, it can be also compared with many other returns, such as the profit rates on financial investments or real investments.

• 수산경영론집
• /
• 제24권2호
• /
• pp.69-82
• /
• 1993

The purpose of this paper is to estimate production function in the coastal fishing, especially long bag set net fishing and trap fishing using Cobb-Douglas production function with the three main variables: fishing quantity per tonage(WQFP), the number of working persons per tonage(WEMP), and the number of utilized fishing equipments per tonage(WEQU). The statistical results of such estimation reveal that fishing quantity per tonage can be expressed as a function of the number of working persons per tonage and the number of utilized fishing equipments per tonage. The estimated coefficients of WEMP and WEQU are statistically significant and also satisfy the requirements of Cobb-Douglas production function. This study also estimates marginal rate of technical substitution of labor in terms of capital (MRT $S_{LK}$ )in each long bag set net fishing and trap fishing. The resuits of this study show us that trap fishing has the technical characteristic of constant returns to scale(CRS) but long bag net fishing has that of decreassing returns to scale(DRS).

• 재무관리논총
• /
• 제9권1호
• /
• pp.221-244
• /
• 2003

This study is aimed to investigate the effects of foreign exchange rates on stock market returns. For the United States, the United Kingdom, Germany, Japan and Korea, the cross-correlation precedence of foreign exchange rate on stock market is found in the case of Germany and Korea. But that of stock market is not observed in any case. We performed three kinds of causality and exogeneity test of Granger test, Sims test and Geweke-Meese-Dent test. The analyses on the full period show the time-lag causal, exogeneous relation of foreign exchange rates with Granger, Sims and GMD test for Korea. The United Kingdom presents the significance with Granger and Sims test while Germany reveals the time-lag relation with Granger and GMD test. When we divide the period into two parts with the Louvre Accord, the first part give the less degree of time-lag relation. But in the second period the three kinds of causality and exogeneity test propose consistent time-lag relation with foreign exchange rates on stock markets for the United Kingdom and Korea with the three test methods. And Granger's test prove German foreign exchange market have a time-lag relation on stock market.

• 유통과학연구
• /
• 제21권5호
• /
• pp.101-111
• /
• 2023

Purpose: The purpose of this paper is to examine the effect of the VKOSPI index on short-term stock returns after a large-scale stock price shock of individual stocks of firms in the distribution industry in Korea. Research design, data, and methodology: This study investigates the effect of the change of the VKOSPI index or investor mood on abnormal returns after the event date from January 2004 to July 2022. The significance of the abnormal return, which is obtained by subtracting the rate of return estimated by the market model from the rate of actual return on each trading day after the event date, is determined based on T-test and multifactor regression analysis. Results: In Korea's distribution industry, the simultaneous occurrence of a bad investor mood and a large stock price decline, leads to stock price reversals. Conversely, the simultaneous occurrence of a good investor mood and a large-scale stock price rise leads to stock price drifts. We found that the VKOSPI index has strong explanatory power for these reversals and drifts even after considering both company-specific and event-specific factors. Conclusions: In Korea's distribution industry-related stock market, investors show an asymmetrical behavioral characteristic of overreacting to negative moods and underreacting to positive moods.

• 한국경영과학회지
• /
• 제41권3호
• /
• pp.1-21
• /
• 2016

The Markowitz portfolio selection model uses estimators to deduce input parameters. However, the estimation errors of input parameters negatively influence the performance of portfolios. Therefore, this model cannot be reliably applied to real-world investments. To overcome this problem, we suggest an algorithm that can exclude stocks with large estimation error from the portfolio by applying a tracking signal to the Markowitz portfolio selection model. By calculating the tracking signal of each stock, we can monitor whether unexpected departures occur on the outcomes of the forecasts on rate of returns. Thereafter, unreliable stocks are removed. By using this approach, portfolios can comprise relatively reliable stocks that have comparatively small estimation errors. To evaluate the performance of the proposed approach, a 10-year investment experiment was conducted using historical stock returns data from 6 different stock markets around the world. Performance was assessed and compared by the Markowitz portfolio selection model with additional constraints and other benchmarks such as minimum variance portfolio and the index of each stock market. Results showed that a portfolio using the proposed approach exhibited a better Sharpe ratio and rate of return than other benchmarks.

• 한국IT서비스학회지
• /
• 제11권3호
• /
• pp.191-203
• /
• 2012

In the stock market, the investors rely on stock information to trade. Good information may stimulate buying, raising the stock prices and the bad information may result in selling, decreasing the stock prices. In terms of the relationship between information and stock prices, stock prices can be viewed as reaction of investors to all the information flowing into the market. The significant increase of web stock news volume is often associated with the significant changes of stock prices. When the web stock news volume for a firm increases significantly, the stock price movement is often oscillatory. This paper attempts to investigate the relationship between volumes of information from Korean web IT and stock prices in Korean stock market. This research shows that when the web stock news volume increases significantly, volatility, trading volumes and rate of returns are increase too. The results of the study provide us with the new clues to the microstructure of the stock market from the perspective of the web news.

• 산업경영시스템학회지
• /
• 제31권3호
• /
• pp.74-79
• /
• 2008

The reinvestment assumption of the internal rate of return(IRR) method may not be valid in an engineering economy study. This situation, coupled with the computational demands and possible multiple interest rate associated with the IRR method, has given rise to other rate of return methods, such as the external rate of return(ERR) method, that can remedy some of these weaknesses. But ERRs are not used generally. We present another rate of return including all attributes of the minimum attractive rate of return(MARR).