본 연구는 기업의 비조세비용과 조세비용이 경영자의 재무보고와 세무보고 의사결정에 어떠한 영향을 미치는가를 분석하였다. 경영자의 재무보고와 세무보고 의사결정 결과는 재무보고이익(법인세비용차감전순이익)과 세무보고이익(과세표준)의 차이로 측정하였다. 첫째, 이익발생기업의 경우에는 내부지분율이 낮거나 부채비율이 높을수록 많은 재무보고이익을 보고하게 되어 재무보고이익과 세무보고이익의 차이가 크며, 조세비용이 클수록 세무보고이익을 낮춤으로서 재무보고이익과 세무보고이익의 차이가 큰 것으로 나타났다. 또한 비조세비용과 조세비용간에는 상충관계가 존재하여 재무보고이익과 세무보고이익의 차이와 비조세비용간의 관계에 조세비용이 영향을 미치는 것으로 나타났다. 둘째, 손실발생기업의 경우에는 내부지분율이 낮은 경우에 재무보고이익을 훨씬 낮게 보고함으로써 재무보고이익과 세무보고이익의 차이가 작은 것으로 나타났다. 부채비율은 이익발생기업과 마찬가지로 부채비율이 높을수록 재무보고이익을 높게 보고함으로써 재무보고이익과 세무보고이익의 차이가 큰 것으로 나타났으나, 손실발생기업의 경우는 조세부담이 적거나 거의 없으므로 조세비용이 재무보고이익과 세무보고이익의 차이에 영향을 미치지 않는 것으로 나타났다.

This study examines the effect of tax and nontax costs on book-tax earnings differences using firm-level tax return data of the Korea Stock Exchange firms during 1999-2000. Previous researches suggest that managers should report both low book and taxable income to minimize tax costs. However, reporting conformity can also impose nontax costs. Managers encounter situations involving a trade-off between financial reporting and tax reporting incentives. This study examines whether inside ownership concentration and foreigner ownership concentration(a proxy for reduced capital market pressure) and debt levels influence these two opposing external reporting incentives. The results of this study are summarized as follows. First, among income firms, the low inside ownership concentration and high debt ratio firms have generally higher financial reporting costs that result in larger book-tax earnings differences. There is a positive relation between tax costs and book-tax earnings differences and the trade-off relation between tax costs and nontax costs. Second, among loss firms, the low inside ownership concentration firms have smaller book-tax earnings differences because of big baths. High debt ratio firms have generally higher financial reporting costs that result in larger book-tax earnings differences. However, there is no positive relation between tax costs and book-tax earnings differences and the trade-off relation between tax costs and nontax costs. This result implies that tax costs play an important role in not loss firms but income firms. Finally, there is no positive relation between foreigner ownership concentration and book-tax earnings differences. This means that foreign ownership concentration is not related to capital market pressure. From a tax policy perspective, these results suggest that book-tax earnings differences may be a less useful indicator of high inside ownership concentration firms, high foreign ownership concentration firms and lower debt level firms because they have fewer incentives to report nonconforming book income.