Executive Summary A wide range of interest groups target the European Parliament (EP) and MEPs have a reputation for being particularly open to diffuse interests, who, due to their limited resources, use 'friendly' MEPs to put pressure on the European Commission and the Council. The notion of the EP representing diffuse as opposed to concentrated interests, conflicts with the broader political science literature on interest groups that dwells on business bias. The general expectation in the literature is for concentrated groups (such as the automobile industry) to prevail over diffuse interests (such as environmental interests). This article considers whether this is a case of conventional wisdom confirmed -or a sectoral exceptionalism. In fact, there are good reasons to doubt the EP's reputation as a policy champion for diffuse interests. Much of our current knowledge about the EP's interest group politics stems from a time when the EP's legislative powers were more limited. Within a relatively short time span the EP has evolved from a token 'multi-lingual talking shop' to, what some researchers have named, one of the most powerful elected legislatures in the world. Arguably, as the powers of the EP have increased, so has attention from interest groups. Few interest groups now dare leave the parliamentary arena to their opponents, and most interest groups adopt a belt-and-braces approach in which 'the institutional trio' (the European Commission, Council and the EP) is lobbied throughout the policy process. The increased powers raises the question of whether the EP still privileges diffuse interests or simply reinforces the advantages of concentrated interests. This question is addressed in this article by examining one recent regulation: Regulation 2011/510/EC on the reduction of CO 2 emissions from light commercial vehicles. Based on processtracing of EU documents and lobbying letters, and interviews with MEPs, EP officials and interest groups, this article shows that the EP is no longer an environmental champion, but instead appears to be more of an environmental pragmatist. Three factors contribute to this change: asymmetric lobbying from industry, a change in the EP's negotiating strategy and increased cooperation between the EP committees. These changes have reduced the privileged position once held by diffuse interests, and provided concentrated interests with r