The efficient market hypothesis gives rise to forecasting tests that mirror those adopted when testing the optimality of a forecast in the context of a given information set. However, there are also important differences arising from the fact that market efficiency tests rely on establishing...

We investigate the dynamics of prices, information and expectations in a competitive, noisy, dynamic asset pricing equilibrium model. We show that prices are farther away from (closer to) fundamentals compared with average expectations if and only if traders over- (under-) rely on public...

This paper examines the comovement of the stock market and of real activity in Germany before World War I under the efficient market hypothesis. We employ multivariate spectral analysis to compare rivaling national product estimates to stock market behaviour in the frequency domain. Close...

Stock prices react significantly to the tone (negativity of words) managers use on earnings conference calls. This reaction reflects reasonably rational use of information. “Tone surprise” -- the residual when negativity in managerial tone is regressed on the firm’s recent economic...

We study the interplay of share prices and firm decisions when share prices aggregate and convey noisy information about fundamentals to investors and managers. First, we show that the informational feedback between the firm's share price and its investment decisions leads to a systematic...

Berkshire Hathaway has realized a Sharpe ratio of 0.76, higher than any other stock or mutual fund with a history of more than 30 years, and Berkshire has a significant alpha to traditional risk factors. However, we find that the alpha becomes insignificant when controlling for exposures to...

The media are increasingly recognized as key players in financial markets. I investigate their causal impact on trading and price formation by examining national newspaper strikes in several countries. Trading volume falls 12% on strike days. The dispersion of stock returns and their intraday...

We examine the effect of close ties with the NSDAP on the stock price of listed firms in 1932-33. We consider not only links between the National Socialists and executives, as was common in earlier work, but also with supervisory board members – whose importance is hard to overestimate in the...

The covered interest parity (CIP) theorem states that the covered interest differential between two similar assets denominated in different currencies should be zero. This paper utilizes high-quality data recorded by the dealers at the Bank of England to test CIP during periods in which news is...

We characterize the divergence between in informational and economic efficiency in a rational expectations competitive market with asymmetric information about the costs of production. We find that prices may contain too much or too little information with respect o incentive efficient...