Asymmetric Price Adjustment: Are IPO Prices too "Sticky"?

Abstract

The study of IPO mispricing is salient because it raises important questions concerning market efficiency and the existence of systematic stock patterns that can be employed by investors to generate excess market returns. The purpose of this paper is to investigate the informational efficiency of IPO market prices with respect to the first 3 trading day’s return and to examine the effect of varying investor sentiment on this information efficiency.  Under traditional definitions of market efficiency, asset prices, including IPO prices should fully reflect all available and relevant information (Fama 1970).  An increasing body of empirical evidence, however, suggests that IPO prices are not efficient as evidenced both in the short run and the long run.  The speed of incorporation of new information into stock prices is critical to many central issues in financial research, such as market efficiency, arbitrage, and market structure. This paper analyzes the speed of price adjustment to information events for IPOs. The setting of the immediate aftermarket presents an opportunity to investigate the issue when little or no trading history exists. In such a setting, investors are more exposed to new information because they cannot observe the stock price behavior or the reactions to previous information signals.