The European Parliament (EP) has become an increasingly important lobbying venue for business due to the recent enhancement of its regulatory powers. Existing research, however, disagrees on the extent to which the intensified business lobbying has resulted in increased business influence on EP policy outcomes. Some studies find a ‘business bias’ in the EP, while others still perceive it to be a forceful promoter of diffuse interests (such as consumer and environmental groups). This article examines the conditions under which business groups shape policy outcomes in the EP. The article uses a comparative qualitative case study design of four recent legislative dossiers, and draws on process‐tracing of EU documents and lobbying letters, and 145 interviews. It finds that the ability of business to leave its fingerprints on EP reports depends on a number of factors – most notably business unity, low issue salience and dossiers being dealt with by mainstream committees.