This paper provides new evidence concerning the probability of informed trading (PIN) and the PIN-return relationship. We take measures to overcome known estimation biases and improve the quality of quarterly PIN estimates. We use the average of a firm’s PIN estimates in four consecutive quarters to smooth out the effect of seasonal variation in trading activities. We find that when high-quality PIN estimates are used, the Fama–MacBeth cross-sectional regressions show stronger evidence for the positive PIN-return relationship than documented in the prior literature. This finding is robust to controls for the January, liquidity, and momentum effects.

Collateral frictions have a profound effect on our economic landscape, ranging from the design of financial securities, laws, and institutions, to various rules and regulations. We analyze a model with disagreement, where securities and collateral requirements are endogenous. It shows that the security that isolates the variable with disagreement is “optimal” in the sense that alternative securities cannot generate any trading. In an economy with N states, investors may introduce more than N securities, and markets are still incomplete. The model has several novel predictions on the behavior of basis—the spread between the prices of an asset and its replicating portfolio.