Experts are important actors of organizational control. Nevertheless, experience suggests that they must be controlled as well. This is particularly the case for traders in financial institutions. We first identify the limits of traditional control patterns when the managing the activities of experts is at stake. Hyperspecialization, which is the ability to act within different logics and multiple time horizons, suggests that multidimensional representations of these activities be adopted and made explicit, which has the potential to prevent such activities from turning problematic. By examining bank risks and conducting additional interviews with actors from bank trading services, we recommend that multiple components of complexity be preserved when dealing with expert‐related operational risks, instead of reducing this complexity to a single concept. Such an approach implies to turn back expertise against itself. Copyright © 2017 ASAC. Published by John Wiley & Sons, Ltd.