개별기업의 산업간 다각화가 자기자본비용에 미치는 영향: 한국기업을 중심으로

This paper examines the potential effect of corporate industrial diversification on cost of equity capital for Korean firms. Corporate industrial di- versification is defined as a strategy by which a company conducts its businesses in multiple industries or markets at the same time for various purposes, such as pursuing a persistent growth and/or reducing firm risk. Given an increasing trend of corporate industrial diversification around the world, previous research in accounting and finance area has mainly analyzed the effect of corporate industrial diversification on firm value. Lang and Stultz (1994), Berger and Ofek (1995), and Rajan et al. (2000) conclude that corporate industrial diver- sification may cause a discount of firm value since the resource allocations within more diversified firms become less efficient. This is due to the overinvestment of internal funds into projects with low returns and/or excessive subsidies of highly performed segments on the other segments and/or overheated competitions among segments. To the contrary, Lewellen (1971) argues that negatively correlated cash flows from individual segments of more diversified firms may reduce the volatili- ties of firm-level cash flows and that such firms’ enhanced ability to raise more debts may increase firm values through greater tax saving effects. Mansi and Reeb (2002) also suggest that industry diversification may have a positive effect on the sum of creditors’ and shareholders’ wealth. Furthermore, by using a more refined measure of industry diversification, Villalonga (2004) finds that the values of more diversified firms increase. In sum, prior research which examines the effect of corporate industry diversification on firm value has reported mixed results. To reconcile those mixed results, recent U.S. based studies begin to examine the effect of industry diversification on cost of equity capital, excluding its effect on future cash flows, both of which determine firm value. Demirkan et al. (2008) suggest that costs of equity capital of more diversified firms will increase because of their higher information risk which is caused by greater agency costs. To the contrary, Hann et al. (2009) argue that costs of equity capital of more diversified firms will decrease since their reduced volatilities of firm-level cash flows may reduce their systematic risks. Thus, whether corporate industry diversification has positive or negative effect on cost of equity capital is still an open empirical question. Furthermore, given that the purpose of industry diversification may differ across U.S. and Korean firms, which leads to a differential effect on cost of equity capital across countries, a separated research for Korean firms is called for. In an ex-ante sense, more diversified firms may decrease their costs of equity capital through reduced volatilities of future cash flows and/or appropriate cross- subsidies among segments. However, it is also possible that costs of equity capital of more diversified firms increase since such firms may overinvest their internal funds into riskier projects and/or take excessive debts for diversification and/or have higher information risks due to greater agency costs. By using 890 Korean firm/year observations between 2001 and 2005, we find that number of segments is negatively associated with cost of equity capital even after well-known risk proxies are controlled for. Thus, we conclude that more industrially diversified Korean firms decrease their costs of equity capital. This is the first study to examine the effect of corporate industry diversification on cost of equity capital for Korean firms. We believe that our empirical evidence may shed some lights on our understanding of the potential effect of corporate industry diversification on various aspects of firms.