The efficient market hypothesis suggests that market prices fully reflect all publicly available information. However, practitioners and regulators are uncertain about the validity of this assumption. The questions Bloomfield raises are: If market prices truly reflect information, why do investors waste effort trying to identify mispriced stocks? Why do managers try to hide bad news in footnotes? And why are regulators trying to stop them? Robert J. Bloomfield presents an alternative to the EMH called the Incomplete Revelation Hypotheses. The HRI suggests that more expensive statistical data attracts less commercial interest. Therefore, information that is more costly to extract from publicly available information is not fully reflected in market prices. Information is hidden due to noise from traders trading randomly. This noise creates an equilibrium in which enough investors purchase costly information in order to realize gains equal to the costs of collecting information. HRI also implies that the more informed investors are, the more complete market prices will be and the lower the gain will be for each investor trading on the basis of this knowledge. If there are very few informed investors, the gain will be greater than the cost of extracting this information. Likewise, if there are too many informed investors, the gain will not be enough to cover the cost of this information. Therefore, equilibrium requires fewer traders to collect costly information. Bloomfield emphasizes the use of statistics extracted from data rather than the use of the data itself. Few investors trade based on costly statistics, which means the markets do not fully reflect these costly statistics. These statistics are also data that, for many, is expensive information because the costs exceed the gains, so trading with less information does not always imply irrationality. However, traders can also make noise based on their irrational and unpredictable sentiment changes. Reliance on unreliable data, aggressive trading by investors with little information, and collection of inappropriate information help to understand overreactions. Conclusion Many people believe that the efficient market hypothesis is ineffective, and Bloomfield presents an alternative to this hypothesis. Bloomfield posits that the meaning of costly statistics is not fully revealed in the market. Some investors place more importance on certain statistics than others, indicating that certain statistics are less exposed to market prices. The HRI essentially extends the EMH by identifying the costs of extracting statistics from publicly available data.