A notable part of criticism of the existing ISDS regime is based on the claim that arbitration, developed for the purposes of addressing commercial disputes, is not fully adequate for the public law-based investor-state controversies. In recent years the discussion of the perils of personal, institutional and procedural synergies between international commercial arbitration (ICA) and investor-state arbitration has been intense. However, a question may arise whether parts of experience acquired in the practice of ICA may be reconceptualized for the purposes of the reformed field of investor-state dispute resolution. Comparative analysis has been widely described as fundamental to the practice of ICA to the extent unparalleled by any other legal field. The paper explores to what extent the famous arbitral ‘comparative mindset’, intrinsic to ICA, can be employed in addressing investment disputes, and what are its limitations in interpreting instruments which regulate investment relations.