Interest groups do not only attempt to influence European legislation by devising and executing their own strategies, or relying on their allies. Almost 50% have also experience in hiring political consultants. Using novel survey data from the policy formulation stage, this study shows that business interest groups are more likely to hire consultancies than non-business interest groups. It suggests that business associations' higher likelihood of hiring consultancies is linked to membership promotion. For firms, it likely relates to their need for specialised lobbying tools and trust-building measures when seeking private goods from policy-makers. Furthermore, the results indicate that consultancy hiring by business interest groups becomes less likely the more they focus on lobbying. This moderation effect highlights that business interest groups show awareness of principal-agent problems and take mitigating action.