Why is the mere announcement of an open-market share repurchase program, which involves no commitment to purchase shares, regarded as good news by the market? We develop a theoretical model to resolve this puzzle. The model predicts that firms with large underpricing can attract attention from speculators by announcing repurchases, and the subsequent trades from these speculators lead to value corrections. Firms with small underpricing, however, cannot attract attention by announcing repurchases, and these firms have to use costly share repurchases as a value-correcting signal. We then provide empirical evidence corroborating the predictions of the theoretical model.

Cumulative abnormal returns (CARs) computed around acquisition announcements are widely considered to be market‐based assessments of expected value creation. We show, however, that announcement returns do not correlate with commonly used and new measures of ex post outcomes. A simple characteristics‐based model using standard information known at the announcement date can predict these outcomes reasonably well, yet CAR even fails to capture the predictions from this model. Evidence suggests that information about the stand‐alone acquirer dominates CAR, making it virtually impossible to extract deal‐related information. We conclude that CAR is an unreliable measure of expected value creation.