The literature on business lobbying has shown that firms increasingly extend their interest representation activities from the domestic to the European level. Consequently, over the last 20 years, individual firms have become influential political actors in Brussels. Yet, after nine years of full membership, eastern European (EE) corporations stay away from EU‐level policy‐making. This article argues that the institutional structures emerging in post‐socialist countries constitute obstacles to firms developing the necessary capabilities for supranational lobbying. While firms in London and Brussels become increasingly professional in their lobbying strategies, large post‐socialist firms handle lobbying exclusively at the highest level of the organizational hierarchy through informal interpersonal networks. It is argued in the article that the confinement of lobbying strategy to the top echelon of corporate management reduces its effectiveness and scope. Consequently, EE companies are unable to integrate into EU lobbying.