Directors of solvent companies owe a fiduciary duty to shareholders qua the company. If a company becomes technically insolvent, the duty switches to the company’s creditors. This is uncontroversial. However, the duty is also said to switch some point before, i.e., in the ‘vicinity of insolvency’. Therefore, directors must be able to make decisions which do not prejudice shareholders, in a way that is free from exposure to claims by creditors. This uncertainty stems from the case law, where the rules of company law have been confused with the policies underlying insolvency law. The two bodies should be considered separately despite their interrelationship in practice. Doing so reveals the proper and fair function of the duty. Its application should be limited to cases of actual insolvency only. While exceptions may be made for cases of irresponsible or negligent risk-taking, this should be the exception – not the rule. This essay is the first of two parts, and examines the emergence of the duty and possible justifications.