The constitution of a company provides for the corporate powers of the company and stipulates how its directors, officers and agents are to exercise such powers on its behalf. For outside parties dealing with the company in contracts or transactions, legal consequences do arise where company officers exercise corporate powers on behalf of the company without the requisite authority or outside the provisions of the company’s constitution. In order to minimize the risk for outside parties and prevent the company from evading contracts or transactions duly made on its behalf by its officers, the rule of presumption of regularity allows outside parties to make the assumption that officers exercising corporate powers act with authority and in compliance with the internal management rules of the company. This article examines the exercise of corporate powers by company officers acting without authority in relation to outsiders who deal with the company in the normal course of business. This article considers the limits to which outside parties are protected by the rule of presumption of regularity as originally enunciated under common law and as enacted in the Companies Act 2020.