Does XBRL Adoption Constrain Managerial Opportunism in Financial Reporting? Evidence from Mandated U.S. Filers

In this study, we examine whether XBRL disclosure (i.e., interactive data submissions) reduces the magnitude of accounting accruals for firms during SEC mandated years. Using mandated XBRL filers, we first compare the magnitude of absolute discretionary accruals in the XBRL-adoption quarters with that in the non-XBRL-adoption quarters. This comparison shows that absolute discretionary accruals decreases significantly from the pre-XBRL-adoption period to the post-XBRL-adoption adoption period. This finding is in line with the view that the XBRL adoption constrains managerial opportunism in financial reporting in general and opportunistic accrual management in particular. Our analyses further reveal that the use of standardized official XBRL elements significantly reduces levels of discretionary accruals in the post-adoption period, while the use of customized extension elements does not. This result is consistent with the view that the former discourages opportunistic accruals management more effectively than the latter by improving transparency and comparability in financial reporting