AbstractThis paper addresses the debate over aggressive tax‐planning models and analyzes the role of tax consultants. It focuses on the dynamic interaction between innovation and imitation of aggressive tax‐planning products and governmental tax regulation, and it highlights the importance of the length of regulatory lag in comparison with the time it takes the tax‐consulting industry to imitate newly innovated tax‐avoidance products. It reveals an alignment of interests between highly innovative tax‐consulting firms and the governmental tax legislator/regulator. The conclusions are also relevant for the policy debate on mandatory disclosure rules about aggressive tax‐planning models.