Do Managers Use Extension Elements Strategically in the SEC's Tagged Data for Financial Statements? Evidence from XBRL Complexity

This study examines whether firm use of XBRL extension elements increases the complexity of mandatory SEC filings. Using the ratio of extension elements to total elements in XBRL 10-K filings as the measure of XBRL complexity, we find that firms' XBRL filings are more complex when the firms are performing poorly, an effect that is more pronounced when firms are more complex. Furthermore, complex XBRL filings are associated with less (more) persistent positive (negative) earnings. Collectively, our results are consistent with managers using extension elements strategically to increase XBRL complexity, obfuscating XBRL-tagged financial information.