Committee coordinators face a classic delegation problem when assigning reports to their committee members. Although a few theoretical developments have focused on the effects of expertise on delegation, empirical studies have commonly assumed monotonic effects. Based on existing informational models, we argue that a more loyal committee member, everything else being equal, is more likely to be appointed as a rapporteur and that more expertise, holding preference divergence constant, has anon-monotonic effect because of informational credibility. Employing accumulated committee service as an expertise measure, these theoretical expectations are tested on all committee report delegations in the European Parliament from 1979 to 2014. Our empirical analysis with non-parametric and parametric hierarchical conditional logit models renders strong support for these expectations. The results hold across member states, political groups, procedures, committees and over time.