This study examined whether the effects of introducing a consolidated tax filing system, as argued in recent literature-based studies, are empirically valid. First, by expanding the sample of Lee Kwang-jae (2001), we analyzed the differences in tax equity borne by individual corporations and consolidated corporations under the current tax system, and examined whether the tax equity borne by the parent company of a consolidated group differs between consolidated and separate tax filing. Second, to examine the corporate tax reduction effect of consolidated filing—which depends on whether consolidated groups minimize taxes by transferring intercompany transaction profits under the current tax system—we developed hypotheses regarding intercompany transaction profit (GAIN), effective tax rate (TR), pre-tax income (EBGT), and deductible net operating losses (LOSS), and tested them through regression analysis. In the tax equity analysis comparing individual and consolidated corporations, the coefficients of variation for consolidated and individual corporations did not show statistically significant differences. In the tax equity analysis of consolidated versus separate filing conducted on parent companies of consolidated groups, the effective tax rates under consolidated and separate filing showed statistically significant differences, and the coefficient of variation under consolidated filing increased substantially compared to separate filing. These results refute the enhancement of tax equity through consolidated filing that has been consistently argued in recent literature-based studies. The regression analysis results were largely consistent with the hypotheses of this study. In both regression models, the coefficients of TR, EBGT, and LOSS all showed signs consistent with the hypotheses, and the coefficients of TR(j) and EBGT(j)—added to verify the validity of hypotheses tested through TR and EBGT—also showed signs consistent with the hypotheses. These analytical results imply that Korean consolidated groups are already minimizing the overall tax burden of the consolidated group through intercompany transactions even under the current tax system. This refutes the empirical validity of the corporate tax reduction effect from consolidated filing that many recent studies have vaguely speculated about. Through three empirical analyses, this study refuted two representative expected effects of introducing the consolidated tax filing system as argued in recent studies. According to the findings of this study, the introduction of a consolidated tax filing system is predicted neither to contribute significantly to enhancing tax equity for consolidated corporations, nor to cause the serious reduction in corporate taxes that tax authorities have been concerned about.