Previous research documents significant abnormal net selling by insiders prior to seasoned equity offering announcements. This study documents that the abnormal net selling is significantly greater for growth firms than for mature firms. It also shows that growth firms experience poorer post‐issue long‐term price performance, which suggests greater overpricing for growth firms. Further analysis shows that greater insider selling prior to the offering announcement is associated with a greater price run‐up prior to the announcement and is not associated with a more negative market reaction to the announcement. Overall, the results suggest that investors may be overly optimistic about future prospects of growth firms.