Abstract:
Currently, the range of contracts stretches from simple contracts, such as bilateral contracts to complex multilateral contracts. Business advancements have created environment for relationships that could not have been completed by bilateral contracts. Although, multilateral contracts may be void or voidable, void and voidable multilateral contracts affect the legal status of all parties. Regarding this concern, the study gathers opinion amongst the scholars and the Supreme Courts judgment, and performs comparative analysis focusing on similar legal provision of England, the Italian Republic, the Federal Republic of Germany and the French Republic in several issues: Moreover, the author also aimed to study economic concepts relating to all those issues and use economics analysis of law to solve problems. From the study, the author found that multilateral contracts are the agreement of more than two parties to establish legal relationship among themselves, and the performances of each of them are directed to the accomplishment of a common objectives. Moreover, from the study, the author found that the section 173 of the Thailand Civil and Commercial Code, Partial invalidity can be divided between partial invalidity of clauses or contents, and partial invalidity of contractual relationship. So the partial invalidity of contractual relationship can be found in void multilateral contracts. However, if multilateral contracts are voidable, when the voidable multilateral contracts are avoided, the whole contracts are void, the section 173 cannot be used. Furthermore, not given by law for any party to claim another party for the damages or compensations of void contract. In voidable contract, if is not possible to restore to the condition in which parties were previously from the beginning, they could be indemnified with an equivalent, but they cannot be claimed another party for the other damages or compensations, unless they use the law of wrongful acts (tort or delict). In addition, the one party who made a declaration of intention under a mistake in multilateral contracts, the unilateral-mistakes party can allege its nullity under the section of 156, and can avoid contract, under the section of 157. Unilateral Mistake adds costs and contingencies to other good-faith parties in multilateral contracts. Therefore, the author suggests that by using the principles of interpretation, the section 173 can be divided between partial invalidity of clauses or contents, and partial invalidity of contractual relationship. The author also proposes that partial avoidance or partial invalidity provisions be enacted based on voidable multilateral contracts. In addition, adding provision, or using the principles of interpretation to consider reliance loss or positive interest compensation for liability in damages of the person who be faulted on pre-contractual liabilities. Then amendment to the Thailand Civil and Commercial Code, should be add a new rule of the section of 156 and 157, unilateral mistake is cause of the invalid multilateral contracts when it is recognizable by the other contracting parties. Finally, the section of 162 should be amended to include multilateral acts.