• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.483-492
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• 2007

• The Korean Journal of Financial Management
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• v.16 no.1
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• pp.83-114
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• 1999

본 연구는 우리나라 기업지배권 시장에서 합병일 이후 합병기업 주가의 장기성과를 측정하고자 하였다. 이를 위해, 본 연구에서는 1980년에서부터 1994년까지의 15년 동안 이루어진 120개 합병기업을 대상으로 합병일 이후 3년 동안 합병기업 주식의 초과수익률을 추정하였다. 실증분석 결과, 전체표본(N=120)의 경우 합병일 이후 3년 동안 합병기업 주식의 누적초과수익률과 매입-보유 초과수익률의 값이 모두 마이너스를 나타내고 있으나 통계적으로 유의성이 없어, 합병일 이후 합병기업의 장기성과가 존재하지 않는다는 귀무가설을 기각하지 못했다. 그러나, 동일 계열기업을 합병한 합병기업의 부표본(N=105)과 비상장기업을 합병한 합병기업의 부표본(N=92)에서는, 합병기업의 장기성과가 모두 유의적인 마이너스 초과수익률로 나타났다. 그리고, 합병일 이후 합병기업 주가의 저성과 현상은 합병대상기업이 계열기업이면서 동시에 비상장기업일 경우에 더욱 두드러지게 나타난다는 것을 다변량 회귀분석을 통해 발견하였다. 계열기업간 합병 및 비상장기업과의 합병을 대상으로 한 이러한 연구결과는, 우리나라 기업집단의 지배구조와 기업문화와 상당한 관련성이 있는 것으로 생각된다.

• The Journal of Bigdata
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• v.3 no.1
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• pp.13-20
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• 2018

Stock market prediction has been long dream for researchers as well as the public. Forecasting ever-changing stock market, though, proved a Herculean task. This study proposes a novel stock market sentiment lexicon acquisition system that can predict the growth (or decline) of stock market index, based on economic news. For this purpose, we have collected 3-year's economic news from January 2015 to December 2017 and adopted Word2Vec model to consider the context of words. To evaluate the result, we performed sentiment analysis to collected news data with the automated constructed lexicon and compared with closings of the KOSPI (Korea Composite Stock Price Index), the South Korean stock market index based on economic news.

• The Korean Journal of Financial Management
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• v.12 no.2
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• pp.73-93
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• 1995

본 연구는 주식시장에서의 체결가격을 균형가격으로 가정하여 계산된 수익률에 관한 통계추정치의 편의에 관하여 분석하고 있다. 주식수익률의 통계적모멘트를 추정하는 것은 주식가격의 행태를 분석하는 연구 및 사건연구등에서 많은 학자들에 의하여 수행되어 왔다. 기존의 대부분의 연구들은 시장에서 체결된 가격이 그 시점의 진정한 균형가격이라는 가정하에 수익률을 계산하고 이 수익률 자료로부터 수익률의 평균, 표준편차, 외도(skewness), 침도(kurtosis) 등의 통계적모멘트를 추정하였다. 그러나 체결가격은 시장의 규칙에 의해 일정한 호가단위로만 거래될 뿐 아니라 매도 또는 매수호가에 거래됨으로써 진정한 균형가격과의 괴리가 있을 수 있게 된다. 본 연구는 주식호가단위의 불연속성과 매도매수호가의 차이로 연한 통계추정치의 편의에 관한 모형을 도출하여 편의의 크기와 특징을 분석하고, 이를 수정하는 간편식을 도출하여 그 유효성을 검증하고 있다. Gottlieb and Kalay(1985), Ball(1988), Cho and frees(1988)등은 1/8 달러의 최소호가단위로 인하여 발생하는 기존의 분산추정치의 편의를 계산하고 이를 수정하는 간편식을 제시하였다. French and Roll(1986)은 휴일이 포함된 기간의 수익률 분산과 평일 분산추정치의 비율이 기간과 비례하지 않는 원인중 하나는 매도매수호가차이로 인한 분산추정치의 편의라는 점을 설명한 바 있다. Choi and Shastri(1989)는 Black and Scholes 옵션가격 결정모형 이 주식 분산값의 크기에 따라 일정한 편의를 보이는 주요한 원인은 퍼센티지 매도매수호가차이와 옵션가격이 모두 진정한 분산치의 정의 함수이기 때문이라는 점을 보였다. Harris(1988)와 최종연(1994)는 주가의 불연속성 및 매도매수호가차이를 동시에 고려하여 기존의 분산추정치가 어떠한 편의를 보이는지에 관하여 분석한 바 있다. 본 연구에서는 최종연(1994)의 연구에서 도출된 모형을 연장하여 국내 주식시장과 같이 주가 수준에 따라 최소호가단위가 변화할 때의 변형모형을 도출하였다. 또한 이 모형에 따라 통계추정치의 편의를 수익률의 표준편차를 중심으로 계산하여 그 정도를 미국시장의 경우와 비교하였고, 그 추정치의 수정 방법에 대하여 호가단위가 변화하는 주가금액이 10,000원 주변일 경우를 중심으로 분석하였다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.1
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• pp.48-55
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• 2019

Current studies have been reported that fruits such as berries may contain both antioxidant and antitumor polyphenols that may be important in this regard. We investigated the immunostimulatory effect of fermented blueberry (Vaccinium corymbosum L.) on cyclophosphamide-induced immunosuppression in animal model. Rats were administered blueberry yeast fermented powder (BYFP) at doses 30, 100, and 300 mg/kg for 4 weeks after cyclophosphamide (Cy) treatment, respectively. The immunomodulatory effect of BYFP were measured both in vitro and in vivo, and the changes of blood components were also analyzed. We found that BYFP recovered immunosuppression-mediated decreased liver, spleen, and thymus weights as well as up regulation of white blood cell, lymphocyte, and neutrophil in blood. Moreover, BYFP up-regulated IL-2, TNF-${\alpha}$, and IFN-${\gamma}$ pro-inflammatory cytokine production compared to immune suppressed control group, respectively. According to histological studies, BYFP regenerated significantly on Cy-mediated injured spleen at the high doses (BYFP 300) comparison with Cy-treated groups (immunosuppression). Collectively, these findings suggest that BYFP may have the potential as a dietary immunostimulatory agent.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.331-339
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• 2003

We investigate long-run relationships between industry relatedness, operating performance, and stock performance after equity carve-outs(ECO). For homo-industry ECOs, 12-month CAR of subsidiary firms is 26.52% and significantly positive at the 5% level and BHAR is 22.19%. For hetero-industry ECOs, subsidiary 12-month CAR and BHAR are 35.14% and 39.64%, respectively, which are significant at the 1% level. On the other hand, long-run performance of parent firms is insignificant for any sub-sample. Excess operating performance of subsidiaries is significantly positive at the first year and insignificant thereafter. The lower the offering ratio is and the better the operating performance is, the better the subsidiary stock performance is. Unlike IPOs and SEOs, shareholders of subsidiaries benefit from ECOs and parent stocks do not underperform. Hetero-industry ECOs improving corporate focus are more effective restructurings than homo-industry ECOs.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.23-31
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• 2013

In Korea, middle and small-sized company takes up an absolute majority of all businesses, and most of them are founded as a limited company. Yet, it is a type of business that fits a company of certain size, and its establishment process is complicated due to various reasons such as investor protection. It is also required to have strict organization structure based on the principle of separation of ownership and management. Accordingly, as the principles may undermine entrepreneur's will to start business, there has been dramatic change in legal system on business establishment and management since 2010. The changes include streamlined process at the foundation stage and digitalization of many regulations on business establishment and operation for more convenience in starting business. Also, new business types for small-sized companies were adopted, and freedom to select business name has been enhanced. The issue of non-par value stock has been allowed, and various types of stock have been adopted for more convenient financing, defense against hostile M&A, and easier business succession.

• The Korean Journal of Financial Management
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• v.26 no.2
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• pp.93-112
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• 2009

The purpose of this study is to examine market timing and volatility timing abilities in Korean equity funds by distinguishing 'skill' and 'luck' for individual funds. In this study, we use the funds, which exist more than consecutive 24 month non-overlapping periods. This procedure leaves 545 funds among total 1,904 funds during sample priod January 2001 to December 2007. To derive the 'luck' distribution, the cross-sectional bootrap approach is adopted. From our results, it is found that when the traditional regression approach is adopted, only few Korean equity funds possess market timing and volatility timing abilities. However, based on the 'luck' distributions, which are derived from cross-sectional bootstrap approach, it is found that market timing and volatility timing abilities of Korean equity funds are merely from 'luck' rather than 'skill'.

• Korean Journal of Construction Engineering and Management
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• v.9 no.2
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• pp.146-158
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• 2008

This paper examines the relationship between the real estate policies of Korean government and the stock market of Korea. It is the purpose of this paper whether the government policies are effective or not when the Korean government release new real estate policies outlining higher taxes and more housing supply as part of its plan to suppress speculation. This paper studies the properties of daily stock returns of the construction sector in Korea securities market when the government announcements of the real estate policies are released. On the demand side, multiple home owners and those purchasing property for speculative purposes are expected to be hit the hardest If the government policies are effective. The empirical results of this paper show that most of the cumulative abnormal returns(CARs) are statistically significant from the year 2002 to the year 2006 except the year 2004.

• Journal of Service Research and Studies
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• v.10 no.4
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• pp.71-88
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• 2020

CB(Convertible bond) is mezzanine security that have the characteristics of bonds and stocks. From the perspective of investors, the purpose of the research is to empirically investigate the degree of investment efficiency of CB and to suggest efficient investment plans. The research method investigated the maturity interest rate, conversion price, and conversion date for CB, and then linked it with daily stock price fluctuations after the conversion date to determine the degree of investment efficiency and stock conversion effect of CB. As a result of the study, it was analyzed that the ratio of the conversion price exceeded days was only about 1/4 of the conversion date, so the investment efficiency was low. The conversion day yield was -6.3% on average and the maturity day yield was -5.2% on average, showing a minus return on average, which was calculated differently from investor expectations. It was analyzed that the number of stocks with a minus conversion day is 2.4 times greater than the number of plus stocks and 3.7 times more than the number of plus stocks with a minus maturity return, so the expected return on stock conversion of CB is low. The research contribution was derived from the problem that the expected rate of return of CB is not high, and it is that the investor's point of view when purchasing CB was established.