XBRL재무제표를 자진 공시한 기업들의 특성과 공시효과

XBRL facilitates financial statement users' acquisition and integration of relevant financial information within a firm's financial reports. The enhanced access and monitoring of financial information by public users improve the transparency of firms' financial statement information. Thus, the decision of voluntary disclosure for XBRL-coded financial statements during a trial period depends on the transparency of firms' financial information. That is, firms with relatively transparent financial reporting are more likely to engage in the financial reporting based on XBRL. This study examines the characteristics of the firms that disclose XBRL-coded financial statement voluntarily. We expect that the firms conducting financial statement reporting using XBRL have more transparent accounting information relative to the firms which do not. The sample consists of the listed firms on KSE and Kosdaq during the trial period of XBRL reporting, i.e., from September in 2006 to August in 2007. From the initial sample, we exclude the firms without financial reporting, those belonging to financial industry and those with no financial information in TS2000 database. Consequently, the final sample consists of 861 firms and among those, 155 firms (18%) conducted the XBRL-coded financial reporting and 706 (82%) firms did not. We use nine variables to measure a firm's accounting transparency: discretionary accrual, non-discretionary accrual, account receivable, depreciation, selling, general & administrative expenses, asset quality, leverage, the ownership of the largest shareholders, and the ownership held by foreign investors. And then, we compare the differences in such variables between the XBRL reporting firms and non-XBRL reporting control firms. The empirical evidence based on univariate and multivariate logit analyses is consistent with the expectation. First, the XBRL reporting decision is positively and significantly related with the foreign ownership, suggesting that the firms with more foreign investors who require transparent financial reporting are more likely to conduct XBRL reporting. Next, as the discretionary accruals and selling, general & administrative expenses (for KSE firms) decrease and the non-discretionary accruals (for Kosdaq firms) increase, firms are more likely to choose XBRL reporting. It also suggest that the likelihood of XBRL reporting increases when their accounting transparency is better. In addition, we examine the change in stock price around the disclosure of XBRL-coded financial statements. If market participants recognize the implication of XBRL reporting on firms' reporting transparency, the firms conducting XBRL reporting will show positive abnormal return around the disclosure day. The results are consistent with the expectation. The mean abnormal returns at the disclosure day(t=0) and the previous day(t=-1) are positive and significant. Further, the mean cumulative abnormal return during the event period (i.e., t=-1～0) is also positive and significant. The positive abnormal returns suggest that the XBRL reporting enhances investors' confidence on firms' accounting transparency and reduce the information asymmetry between corporate insiders and outside investors. When we compare the announcement effect between KSE firms and Kosdaq firms, while there is no difference in the time-trend of stock prices, the mean cumulative abnormal return is significant for KSE firms only. Interestingly, when we examine the announcement returns of annual XBRL reporting and quarterly XBRL reporting separately, those based on annual reporting are more significant economically and statistically rather than those based on quarterly reporting. This result suggests that the effect of XBRL-coded financial reporting on the reduction in information asymmetry depends on the type of financial reporting. The finding of this study that financial reporting through XBRL is significantly associated with financial transparency encourages regulatory enhancement for XBRL reporting.