Many large corporations have recently adopted antitakeover charter amendments which make the transfer of corporate control more difficult. This paper develops and tests competing theoretical explanations for the passage of these amendments. In one view, antitakeover provisions are adopted because incumbent management seeks job protection at stockholders' expense. The alternative hypothesis is that antitakeover provisions benefit stockholders, perhaps by extracting greater payment in exchange for corporate control. Although inconclusive, the evidence provides weak preliminary support for the hypothesis that antitakeover amendments are best explained as a device for managerial entrenchment.