채무불이행시 대체거래(Substitute Transaction)로 인한 손해배상액 산정에 관하여 －구체적 사례와 민법 개정방향을 중심으로－

A “substitute transaction” refers to a transaction made by one party of a contract with a third party in the event of a breach by the other party, with the aim of achieving the same objective as the original contract. The purpose of a substitute transaction is often to minimize damages, aligning with the obligation of creditors to mitigate losses resulting from the breach. In Korea, contractual damages are mainly assessed based on the market price. When the substitute transaction price is identical to the market price, there is no distinction between assessing damages based on the market price (abstract assessment) and the substitute transaction price (concrete assessment). However, certain situations may arise where it becomes challenging to prove the market price or where the substitute transaction price deviates from the market price. In the latter case, the burden falls on the damaged party to demonstrate the necessity of entering into a substitute transaction at a price higher or lower than the market price, as well as the foreseeability of this requirement by the non-performing party. Given the practical difficulties in proving these elements, the disadvantaged party tends to be the damaged party rather than the non-performing party. In light of this, having a dedicated provision in civil law addressing concrete assessment can offer a more efficient and expeditious remedy for the damaged party. Concrete assessment has already been acknowledged and more explicitly incorporated into recent international norms and regulations in several European countries. Notably, the United Nations Convention on Contracts for the International Sale of Goods (CISG) provides a relevant example, with numerous cases accumulating over time. In most international norms, it is required that the damaged party avoids the contract before seeking damages through concrete assessment. In Korea, a proposed revision of the civil law advocated for the inclusion of a new provision on concrete assessment, even without mandating preemptive avoidance. However, this proposal did not make it into the final draft. Nevertheless, when considering the balance of interests between contractual parties, we should actively consider adopting concrete assessment to provide a more effective remedy for the damaged party.