Abstract Since 1989 the European Commission has attempted to harmonise rules governing EU takeovers as a crucial step towards the integration of Europe's capital markets. The article takes its starting point in the vote in the European Parliament in July 2001, which turned down a proposal for a Takeover Directive. Members of the European Parliament overwhelmingly voted according to national rather than party lines, which is unusual. The article develops an explanation for opposition to the directive, which emphasises differences between national systems of corporate governance. The outcome is asymmetric vulnerability, which means that the likelihood of a company becoming the target of an unwanted takeover bid differs depending on the nature of national incorporation. The article shows how national differences constituted obstacles to real reform within a context of arguments about how to create a level playing field. © 2017 Wiley. All rights reserved.