Do insiders time their trades? Evidence from Euronext Lisbon

Abstract

In this paper, we examine the existence of insider trading abnormal profits in Euronext Lisbon from January 2001 to December 2005. Using the methodology of event studies, our overall results show that, in spite of existing legislation to regulate transactions, insiders are still able to make abnormal profits. Results also show that insider buying is a stronger indicator than insider selling and that the magnitude and duration of abnormal profits depend on both firm and transaction-specific factors. These include industry classification, firm size, firm valuation and relative trading volume.