Changes in the Information Efficiency of Stock Prices: Additional Evidence

Previous research shows, using data from three quarters after the implementation of regulation fair disclosure (Reg FD), that there is an improvement in the informational efficiency of stock prices after Reg FD. We compare the informational efficiency of stock prices in four pre-Reg FD quarters (1999–2000) and 12 post-Reg FD quarters (2002–2005). The improvement in the informational efficiency of stock prices previously reported in the immediate aftermath of Reg FD persists in later periods.