This paper considers how estimates of the market model beta parameter can be biased by friction in the trading process (information, decision, and transaction costs) that (a) leads to a distinction between observed and ‘true’ returns; (b) causes observed returns to be generated asynchronously for a set of interdependent securities; and (c) thereby introduces serial cross-correlation into security returns. Several propositions are derived from which consistent estimators of beta are obtained, and the effect of differencing interval length on beta estimates is specified. The formulation is contrasted with the related analyses of Scholes-Williams (1977) and Dimson (1979).

ABSTRACT Exploiting the fact that insiders trade for a variety of reasons, we show that there is predictable, identifiable “routine” insider trading that is not informative about firms’ futures. A portfolio strategy that focuses solely on the remaining “opportunistic” traders yields value‐weighted abnormal returns of 82 basis points per month, while abnormal returns associated with routine traders are essentially zero. The most informed opportunistic traders are local, nonexecutive insiders from geographically concentrated, poorly governed firms. Opportunistic traders are significantly more likely to have SEC enforcement action taken against them, and reduce trading following waves of SEC insider trading enforcement.

ABSTRACT We study the impact of social networks on agents’ ability to gather superior information about firms. Exploiting novel data on the educational background of sell‐side analysts and senior corporate officers, we find that analysts outperform by up to 6.60% per year on their stock recommendations when they have an educational link to the company. Pre‐Reg FD, this school‐tie return premium is 9.36% per year, while post‐Reg FD it is nearly zero. In contrast, in an environment that did not change selective disclosure regulation (the U.K.), the school‐tie premium is large and significant over the entire sample period.

This paper employs a new empirical approach for identifying the impact of government spending on the private sector. Our key innovation is to use changes in congressional committee chairmanships as a source of exogenous variation in state-level federal expenditures. We show that fiscal spending shocks appear to significantly dampen corporate investment activity. This retrenchment occurs within large and small states and is most pronounced among geographically concentrated firms. The effects are economically meaningful, and the mechanism--entirely distinct from interest rate and tax channels--suggests new considerations in assessing the impact of government spending on private-sector economic activity.

Management for helpful comments. We also thank Nick Kennedy, Stephen Wilson, Laura Dutson, Matthew Healey, Meng Ning, Courtney Stone, and Bennett Surajat for excellent research assistance. We are grateful to BoardEx and Linda Cechova for providing firm board data, Morningstar and Annette Larson for providing mutual fund data, and to the Chicago GSB Initiative on Global Markets for financial support. This paper uses social networks to identify information transfer in security markets. We focus on connections between mutual fund managers and corporate board members via shared education networks. We find that portfolio managers place larger bets on firms they are connected to through their network, and perform significantly better on these holdings relative to their non-connected holdings. A replicating portfolio of connected stocks outperforms a replicating portfolio of non-connected stocks by up to 7.8 % per year. Returns are concentrated around corporate news announcements, consistent with mutual fund managers gaining an informational advantage through the education networks. Our results

ABSTRACT Using proprietary data on stock loan fees and quantities from a large institutional investor, we examine the link between the shorting market and stock prices. Employing a unique identification strategy, we isolate shifts in the supply and demand for shorting. We find that shorting demand is an important predictor of future stock returns: An increase in shorting demand leads to negative abnormal returns of 2.98% in the following month. Second, we show that our results are stronger in environments with less public information flow, suggesting that the shorting market is an important mechanism for private information revelation.