Abstract: | Most initial public offerings (IPOs) feature “lockup” agreements, which bar insiders from selling the stock for a set period following the IPO, usually 180 days. We examine stock price behavior in the period surrounding lockup expiration for a sample of 2,529 firms from 1988 to 1997. We find that lockup expirations are, on average, associated with significant and negative abnormal returns, but the losses are concentrated in firms with venture capital backing. For the venture‐capital‐backed group, the largest losses occur for high‐tech firms and firms with the greatest post‐IPO stock price increases, the largest relative trading volume in the period surrounding expiration, and the highest quality underwriters. JEL classification: G14, G24 |