The conditional performance of insider trades

This paper estimates the performance of insider trades on the closely held Oslo Stock Exchange (OSE) during a period of lax enforcement of insider trading regulations. Our data permit construction of a portfolio that tracks all movements of insiders in and out of the OSE firms. Using three alternative performance estimators in a time-varying expected return setting, we document zero or negative abnormal performance by insiders. The results are robust to a variety of trade characteristics. Applying the performance measures to mutual funds on the OSE, we also document some evidence that the average mutual fund outperforms the insider portfolio.