The Life Cycle Effects of Corporate Takeover Defenses

We document that the relation between firm value and the use of takeover defenses is positive for young firms but becomes negative as firms age. This value reversal pattern reflects specific changes in the costs and benefits of takeover defenses as firms age and arises because defenses are sticky and rarely removed. Firms can attenuate the value reversal by removing defenses, but do so only when the defenses become very costly and adjustment costs are low. The value reversal explains previous mixed evidence about takeover defenses and implies that firm age proxies for takeover defenses’ heterogeneous impacts on firm value.

Adaptive modelling of variably saturated seepage problems

Summary In this article, we present a goal-oriented adaptive finite element method for a class of subsurface flow problems in porous media, which exhibit seepage faces. We focus on a representative case of the steady state flows governed by a nonlinear Darcy–Buckingham law with physical constraints on subsurface-atmosphere boundaries. This leads to the formulation of the problem as a variational inequality. The solutions to this problem are investigated using an adaptive finite element method based on a dual-weighted a posteriori error estimate, derived with the aim of reducing error in a specific target quantity. The quantity of interest is chosen as volumetric water flux across the seepage face, and therefore depends on an a priori unknown free boundary. We apply our method to challenging numerical examples as well as specific case studies, from which this research originates, illustrating the major difficulties that arise in practical situations. We summarise extensive numerical results that clearly demonstrate the designed method produces rapid error reduction measured against the number of degrees of freedom.