There is historical evidence which suggests that mergers can be a potent agent for change in a transition towards a US-style corporate governance system where widely-held companies play a pivotal role. Moreover, past events suggest that competition law can influence whether ‘transformative’ acquisition activity will occur. Despite this, little has been said in the contemporary discourse on comparative corporate governance about how competition law and mergers might be catalysts for change. This paper seeks to familiarise a European audience with the relevant dynamics. For expository purposes, the analysis will focus on historical events occurring in the United States and the United Kingdom, the country with corporate governance arrangements which resemble America's more closely than any other nation. Nevertheless, there will also be discussion of questions which merit attention from a Continental European perspective, accompanied for illustrative purposes by references to circumstances in Germany.