Reliable proxies for informed trading are required to test many theories in finance. Theory suggests several possible proxies; however, validating these empirically has been challenging because trades by informed investors cannot (in general) be observed. Kenneth Ahern’s new paper, “Do Proxies for Informed Trading Measure Informed Trading? Evidence from Illegal Insider Trades,” addresses this challenge by using hand-collected data on illegal insider trades. He shows that the effective bid-ask spread and the absolute order imbalance are robust predictors of informed trading (illegal insider trading) while other measures are not because of strategic timing of their trades by insiders and sampling bias.
Spotlight by Thierry Foucault
Photo courtesy of Kenneth Ahern