Lojalitetsplikten i långvariga kommersiella avtal – Med särskild utblick mot kvardröjande och framtida förpliktelser

Sammanfattning: The duty of loyalty, also known as the principle of loyalty, is regarded as a general principle of law in Swedish contract law. It implies a duty to observe the interests of the counter-party beyond the regulated obligations in the contract. Different definitions of the duty of loyalty do not give much advice as of how it should be interpreted. Therefore, what is relevant is how the principle is being used. In general the duty of loyalty rests on unstated duties, which originates from the conditions of the specific contractual relationship. The principle’s importance in long-term commercial contracts is uncertain and this thesis makes an attempt to try and clarify the picture with a special focus on the duty of loyalty in joint venture agreements and contracts for building works. At the same time the question is asked whether an omit or breach of the duty of loyalty with success can be invoked in courts as a separate cause of action in support of a claim for performance, damages and/or a right to cancellation. In the light of a relatively new arbitration award the thesis also looks into how the ground for judgement turns out in a dispute regarding the validity of contract clauses, which extends beyond the contractual period and stipulates remaining and/or future obligations. The ambition of the thesis is to study the post-contractual liability on the basis of such obligations, since they are not always performed with reference to the contract being terminated and the regulation of the obligations not being sufficiently detailed to be able to win legal effect after the contractual period has ended. The thesis uses legal dogmatic method and the legal doctrine makes up the main source of information. Case-law is also being regarded in the thesis and although the case-law in a sense disfavours the duty of loyalty, the ethics of the principle in general still seems to influence the legal discourse in higher court and in the Supreme Court. According to the thesis the importance of the duty of loyalty in long-term commercial contracts is totally dependent on the specific situation and much dependent on the type of contract, the position of the parties, the parties expectations and also the character of the specific legal relationship. The thesis shows that the Swedish contract law probably is incomplete when it comes to the judgement of post-contractual obligations and that a greater respect to the strong relation-based foundation in long-term contracts where the duty of loyalty is given an increased role would be able to contribute to a clarification of the legal position and to the development of the law on the area.