The Effect of the SEC's XBRL Mandate on Audit Report Lags

SYNOPSIS: There is considerable debate about whether the adoption of eXtensible Business Reporting Language (XBRL) will result in timelier SEC filings. We provide empirical evidence on this debate by investigating the effect of XBRL adoption on audit report lags. Using a hand-collected panel of Su0026P 1500 clientsu0027 XBRL financial report filings and both levels and difference-in-differences analyses, we show that audit report lags decrease following the mandatory adoption of XBRL. These results are robust to various subsamples and model specifications. On average, audit report lags decrease anywhere from 0.4 to 3.4 percent (0.21 to 1.93 days) in the post-adoption period, depending on the specification used. We further document that these results are concentrated among filers with strong internal control systems and no prior XBRL reporting experience. We also find that audit report lags continue to decline in the years following adoption, which is indicative of a learning curve and improvements in XBRL reporti...