Changes in Equity Ownership and Changes in the Market Value of the Firm

We study the stock price response to announcements of share purchases by corporate insiders over the period 1994 through 1999. The cross-sectional variability in the response is consistent with a curvilinear relation between firm value and insider ownership, where the value of the firm first increases, then decreases as insider ownership increases. These results are consistent with a causal interpretation of the relationship between insider ownership and firm value. The results of further tests are inconsistent with an interpretation that the firms in our sample are moving toward a new equilibrium ownership level or that insiders are purchasing shares to signal that the firm is undervalued.