Greater corporate focus is consistent with shareholder wealth maximization. Diseconomies of scope in the 1980s are confirmed by a trend towards focus or specialization, a positive relation between stock returns and focus increases, and the failure of diversified firms to exploit financial economies of scope (coinsurance of debt or reliance on internal capital markets). Large focused firms were less likely to be subject to hostile takeover attempts than were other firms, but diversified firms were distinguished in the 1980s mostly by being relatively active participants, as both buyers and sellers, in the market for corporate control.

This paper provides large-sample evidence that poison pill rights issues, control share laws, and business combination laws have not systematically deterred takeovers and are unlikely to have caused the demise of the 1980s market for corporate control, even though 87% of all exchange-listed firms are now covered by one of these antitakeover measures. We show that poison pills and control share laws are reliably associated with higher takeover premiums for selling shareholders, both unconditionally and conditional on a successful takeover, and we provide updated event study evidence for the three-quarters of all poison pills not yet analyzed. Antitakeover measures increase the bargaining position of target firms, but they do not prevent many transactions.