Insider Trading Disclosure, Information Asymmetry, and Differential Earnings Relevance as Indicated By Trading Volume

We use buy and sell signals derived from insider trading disclosures to identify experimental-group cases in which decreases in earnings-related predisclosure information asymmetry have arisen through the use of the disclosures. For each experimental firm, each earnings-announcement date is preceded, within 90 days, by at least 2 specific buy or 2 specific sell signals, while none of these signals occurs within 90 days of any control group earnings-announcement date. Our null hypothesis is that mean differences in experimental and control group earnings-announcement-period trading volumes are greater than or equal to similar mean differences occurring over contiguous non-announcement periods. Rejection of our null, for various periods, implies less earnings relevance for our experimental group vis-agrave;-vis our control group as a consequence of decreases in earnings-related predisclosure information asymmetry for the latter. This result is consistent with the view that changes in firms' information environments are the most pervasive factor explaining secular changes in earnings relevance