본 논문은 시장경쟁정도(market competition)와 산업집중도가 역의 상관관계를 가진다는 가정 하에 산업집중도가 기업가치에 어떠한 영향을 미치는지, 그리고 산업집중도가 부채비율에 어떠한 영향을 미치는지에 대하여 2008년부터 2011년 까지 한국거래소에 지속적으로 상장되어있는 845개의 비금융권 기업, 3,380개의 표본을 대상으로 실증분석을 시도한다. 논의의 검증을 위하여, 산업집중도를 측정하기 위한 변수인 허쉬만-허핀달지수(HHI)를 기준으로 경쟁이 심한 시장과 그렇지 않은 시장으로 나누어 분석을 수행하였다. 본 연구의 실증분석 결과, 산업집중도가 낮은 시장에서는 집중도가 기업가치에 음(-)의 영향을 미치며, 부채비율에는 양(+)의 영향을 미치는 것으로 나타났다. 반면 산업집중도가 높은 시장에서는 집중도가 기업가치에 양(+)의 영향을 미치며, 부채비율에는 음(-)의 영향을 미치는 것을 확인할 수 있었다. 즉, 시장상황에 따라 산업집중도가 기업가치와 부채비 율에 유의하게 다른 영향을 준다는 흥미로운 결과를 관찰하였다. 이러한 실증분석결과는 Nickell(1996)의 주장에서처럼 시장상황에 따라 경쟁이 기업가치에 긍정적인 영향을 미칠 수 있음을 암시한다. 그리고, Castanias(1983)를 비롯한 여러 학자들이 파산위험, 세금, 대리인비용 등을 이용하여 설명하고자 했던 최적자본구조의 존재유무가 다른 외부요인인 시장경쟁정도와 관련하여 존재할 가능성을 보여준다. 또한, Myers and Majluf(1984)의 자본조달순위 이론을 뒷받침 해주는 결과라고 해석할 수 있다.
Assuming an inverse association between market competition and industrial concentration, this study empirically investigates how industrial concentration affects firm values and debt ratios. We have analyzed 3,380 observations of 845 non-financial firms that have been consistently listed on the Korea Exchange from 2008 to 2011. Following the Horizontal Merger Guidelines of the U.S. Department of Justice and FTC, we divide the sample data into three sub-groups based on the Hirschman-Herfindahl Index (HHI) values: unconcentrated (i.e., competitive) market if the HHI value is less than 1,500; highly concentrated (i.e., monopolistic or oligopolistic) market if the HHI value is greater than 2,500; or moderately concentrated market if the HHI value lies between 1,500 and 2,500. In doing so, we find that the relationships among the degrees of market competition, firm value, and debt ratios are quite clear and significant in the Korean market. Our empirical results based on regression analyses are as follows. First, industrial concentration affects firm values negatively in an unconcentrated market but, affects the firm values positively in a highly concentrated market. This finding suggests that greater competition among firms enhances firm values in an unconcentrated market. It also suggests that nearly monopolistic or oligopolistic firms can more easily increase their firm values as the competition further decreases. Second, industrial concentration affects debt ratio positively in an unconcentrated market, but, affects it negatively in a highly concentrated market. This implies that fierce competition in an unconcentrated market generally influences firms to be hesitant in using debt financing, whereas lower levels of competition lead to firms increasing their debt ratios due to having less pressure of bankruptcy. In contrast, in a highly concentrated market in which the competition is originally less intense, a further decrease in the market competition encourages the firms that already have market power to decrease their debt ratios because, they have enough internal capital to sustain and operate their business without increasing their debt. The robustness tests support the indications of the regression analysis results. For a group with a low (high) level of industrial concentration determined by their HHI values, industrial concentration is shown to behave positively (negatively) with firm value and negatively (positively) with debt ratio. In other words, the firm-level effects of industrial competition are dichotomous in a cross-section of firms with varying market influences. Our findings have the following implications. First, industrial concentration and firm value have a non-linear relationship. In an unconcentrated market as Nickell(1996) points out, market competition leads firms to perform better. However, in a concentrated market, lower competition increases the value of firms that have monopolistic powers. Second, our finding suggests that the optimal capital structure might be related to the degree of market competition. Finally, the pecking order theory of Myers and Majluf(1984) can be supported by our findings