Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In October 2000, the Securities and Exchange Commission (SEC) passed Regulation Fair Disclosure (FD) in an effort to reduce selective disclosure of material information by firms to analysts and other investment professionals. We find that the information asymmetry reflected in trading costs at earnings announcements has declined after Regulation FD, with the decrease more pronounced for smaller and less liquid stocks. Return volatility around mandatory announcements is also lower but overall information flow is unchanged when mandatory and voluntary announcements are combined. Thus, the SEC appears to have diminished the advantage of informed investors, without increasing volatility.