• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.2
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• pp.75-93
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• 2013

In applying Markowitz's portfolio selection model to the stock market, we developed a comprehensive investment decision-making framework including key inputs for portfolio theory (i.e., individual stocks' expected rate of return and covariance) and minimum required expected return. For estimating the key inputs of our decision-making framework, we utilized an exponentially weighted moving average (EWMA) which places more emphasis on recent data than the conventional simple moving average (SMA). We empirically analyzed the investment results of the decision-making framework with the same 15 stocks in Samsung Group Funds found in the Korean stock market between 2007 and 2011. This five-year investment horizon is marked by global financial crises including the U.S. subprime mortgage crisis, the collapse of Lehman Brothers, and the European sovereign-debt crisis. We measure portfolio performance in terms of rate of return, standard deviation of returns, and Sharpe ratio. Results are compared with the following benchmarks : 1) KOSPI, 2) Samsung Group Funds, 3) Talmudic portfolio based on the na$\ddot{i}$ve 1/N rule, and 4) Markowitz's model with SMA. We performed sensitivity analyses on all the input parameters that are necessary for designing an investment decision-making framework : smoothing constant for EWMA, minimum required expected return for the portfolio, and portfolio rebalancing period. In conclusion, appropriate use of the comprehensive investment decision-making framework based on the Markowitz's model integrated with EWMA proves to achieve outstanding performance compared to the benchmarks.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.39-79
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• 2005

This paper addresses the question of whether a monopolistic banking system can lead to a higher steady state level of capital stock. Information externality has enhanced as the advance of the financial system such as the establishment of the credit bureau system, networking, etc. Hence this paper aims to analyze the effects of both information externality and economic development on the determination of the optimal banking market structure. This paper shows that the presence of information externality together with asymmetric information would explain how a monopoly bank leads to a higher steady state level of capital stock. It also shows that not only under-developed countries but industrialized countries may also benefit from a concentrated banking system. This analysis provides an alternative explanation of the recent deregulation and resulting trends in mergers and acquisitions. This also provides a theoretical foundation to support governments' policy changes toward promoting merger and acquisition activities.

• The Korean Journal of Financial Management
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• v.8 no.1
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• pp.139-153
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• 1991

This paper examines the pecuniary effects stemming from insider trading in the equities of firms targeted for acquisition. Illegal exchanges by those having advantageous information are found to result in excessive returns to stockholders of the sought firms. However, unusual market activities are not typical immediately subsequent to the illegal trading date, suggesting that nonpublic information is synthesized by market mechanisms with sufficient speed so that others cannot profit by imitating the better informed traders. The obtained evidence does not support the contention that insider trading on nonpublic information harms the outsider stockholders of involved firms.

• The Korean Journal of Financial Management
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• v.24 no.1
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• pp.59-83
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• 2007

In this paper, we test empirically free cash flows hypothesis about stock repurchase. The main results of this study can be summarized as follows. First, repurchasing firms do not experience a growth in profitability relative to their peer firms. Second, repurchasing firms experience a contraction in their investment opportunity, and so capital expenditures and cash reserves decline after the repurchase. Third, repurchasing firms experience a decline in systematic risk and investments and in their cost of capital. Fourth, the reduction in profitability and cost of capital are sources of the positive market reaction to the repurchase announcement. And the market reaction to stock repurchase announcements is stronger among those firms that are more likely to overinvest. Conclusively, these results support free cash flows hypothesis. When firms experience a decline in profitability, capital expenditures and cash reserves, systematic risk and cost of capital, they decide to repurchase stocks to reduce free cash flows.

• The Korean Journal of Financial Management
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• v.24 no.1
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• pp.85-107
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• 2007

In this study, I analyzed determinant factors of mutual fund return. The samples was distributed into three types according to the ratio of included stocks in funds. The proxies of mutual funds were set up three ways(returns of fund). As a result of the analysis, I found that growth positively affect to fund return, abnormal return and adjusted abnormal return in all samples. While, according to three types of sample, expected and unexpected fund cash flows had differently effect on fund return. Inferentially, it seemed that the ratio of included stocks in fund was the cause of that. But price pressure hypothesis are not supported. In conclusion, it was not found the possibility of stock market disturbance in this analysis.

• The Journal of Industrial Distribution & Business
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• v.10 no.6
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• pp.51-58
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• 2019

Purpose - Prior studies reported that the opacity of information caused stock price crash. If managers fail to disclose unfavorable information about the firm over a long period of time, the stock price is overvalued compared to its original value. If the accumulated information reaches a critical point and spreads quickly to the market, the stock price plunges. Information management by management's disclosure policy can cause information uncertainty, which will lead to a plunge in stock prices in the future. Thus, this study aims at examining the impact of disclosure quality on crash risk by focusing on the unfaithful disclosure firms. Research design, data, and methodology - This study covers firms listed on KOSPI and KOSDAQ from 2004 to 2013. Firms excluded from the sample are non-December firms, capital-eroding firms, and financial firms. The financial data used in the research was extracted from the KIS-Value and TS2000 database. Unfaithful disclosure firm designation data was collected from the Korea Exchange's electronic disclosure system (kind.krx.co.kr). Stock crash is measured as a dummy variable that equals one if a firm experiences at least one crash week over the fiscal year, and zero otherwise. Results - Empirical results as to the relation between unfaithful disclosure corporation designation and stock price crashes are as follows: There was a significant positive association between unfaithful disclosure corporation designation and stock price crash. This result supports the hypothesis that firms that have previously exhibited unfaithful disclosure behavior are more likely to suffer stock price plunges due to information asymmetry. Second, stock price crashes due to unfaithful disclosures are more likely to occur in Chaebol firms. Conclusions - While previous studies used estimates as a proxy for information opacity, this study used an objective measure such as unfaithful disclosure corporation designation. The designation by Korea Exchange is an objective evidence that the firm attempted to conceal and distort information in the previous year. The results of this study suggest that capital market investors need to investigate firms' disclosure behaviors.

• KDI Journal of Economic Policy
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• v.34 no.1
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• pp.29-52
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• 2012

During the global financial turmoil in 2007-2008, deviation from the covered interest parity (CIP) between the Korean won and US dollar through the foreign exchange swap has escalated in its magnitude beyond 1,000bp in November 2008, and it still persists around 100bp level. In this paper, we examine a newly developed margin based asset pricing model using Kalman filter approach and show that the escalation of the CIP deviation is found to be significantly related to the global dollar funding illiquidity and country-specific funding conditions. Furthermore, we find evidence that the poor funding conditions (or higher margins) are driven by the general money market illiquidity and may lead to higher funding illiquidity, which suggests the reinforcing effects of the liquidity spiral. We also show that the supply of dollar liquidity and improved funding conditions help alleviate the deviations from the parity, however the persistent anomaly is found to be related to the high level of volatility in the FX swap market.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.305-329
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• 2003

This work analyzes the influence of the dollar and yen currency on the rate of return of the individual firms and its symmetries based on the data from Jan. 5 1987 to Dec. 28, 2001. GARCH and autoregressive error models were used for on the daily data, due to the heteroscedascity and autoregression of the error terms, and as for the monthly data, this paper follows the autoregressive error models. Daily data fumed out to be a better explanatory variable in detecting exchange rate exposure, and EGARCH(1, 1) and GJR-GRARCH(1, 1) have higher competence in analyzing the daily data. Also, most of the exposed firms have been exposed in the negative region, and appreciation of exchange rate does not help enhancing the asset value of the domestic value. Analysis on the asymmetries let us conclude that high proportion of domestic firms face asymmetric exchange rate exposure, and that the pricing-to-market theory carries more conviction than the real option theory. Furthermore, monthly data are more precise in analysis of asymmetries.

• Korean System Dynamics Review
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• v.15 no.4
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• pp.5-28
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• 2014

Derivatives can be easily bought by those companies that need to hedge foreign currency debt or foreign currency assets through the financial market, considering their exchange rate exposure from international trade. The derivatives market has been growing rapidly due to the needs for investment and hedging. To manage foreign exchange risk, companies hedge risks through financial derivatives. According to our study, hedging is an effective way to mitigate the impact of exposure to exchange risk, as long as companies are only hedging underlying assets. Yet, covetous attitude toward the profit from derivatives and unexpected changes in exchange rate can cause problems for companies. This study analyzed the structural risks of derivatives with analysis of system dynamics. In particular, many companies suffered substantial loss due to KIKO during the economic crisis. We explained the problem therein through dynamic analysis. In addition, we revealed the structural problem that could cause a sudden spike in losses through simulations.

• Health Policy and Management
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• v.17 no.2
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• pp.68-90
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• 2007

Nurse staffing level is an important factor that influences the quality of health service and patient outcomes. This study was carried out to examine the current state of acute hospital nurse staffing and find out factors that affect the nurse staffing level. Nurse staffing of individual hospitals was measured using the number of registered nurses per 100 beds. Descriptive and multiple regression analyses were conducted using 592 acute care hospitals' data. Regression model included structure factors such as referral level, ownership, medical and general staffing, and financial outcome factors such as occupancy rate, inpatient and outpatient revenues. Market characteristics included strength of competition, supply of nurses, and income and health status level of consumers. The average number of nurses per 100 beds was 28 and showed a great variation according to the referral level. Regression model explained this variation as much as 76.87%. Hospital structure variables which affecting the hospital nurse staffing level positively were ICU bed ratio, the staffing level of specialist, training doctor and employees except doctor and nursing personnel, while the negative factor was nurse aid staffing level. General hospitals employed more nurses than hospitals. Among outcome characteristics, occupancy rate and the amount of health insurance inpatient revenue affected positively on the hospital nurse staffing level. The more supply of the new nurse and the higher consumer income and health status in the medical service markets, the more nurses were employed by the medical institutes. According to the study result, hospitals employed more nurses when they had more financial incentive by increasing nurses. This means appropriate hospital incentive policy and regulation policy, which hospital violate nurse staffing level have to pay penality, should be needed. Clarifying job description between nurses and nurse aids and the reentry program for unemployed experienced nurses will be helpful to increase nurse staffing level.