본 연구는 국제무역거래에 있어 흔히 발생되는 대금지급의 연체에 따른 이자발생과 관련하여 CISG 자문위원회의 공식 의견인 Black Letter Rule을 중심으로 고찰한다. 그 주요 내용으로 제78조의 해석과 제78조에 따른 이자발생의 요건과 이자계산을 상세히 고찰하고, 제78조에 따른 이자율을 정의하기 위한 규칙과 이를 위한 다양한 접근법을 살펴보도록 한다. 이와 더불어 이자율에 있어서의 복리의 적용여부, 이자의 지급, 이자책임에 대한 면책, 이자청구의 중단, 채권자의 추가손실, 입증책임에 대하여 살펴본다. 이와 더불어 본 연구는 이자지급에 있어 이자율에 대한 관련 기존 판례 및 학설을 검토한 후 이를 CISG 자문위원회의 공식의견과 상호비교 검토함으로 이자지급에 있어 이자율에 관련된 원칙을 재정립하고 이에 따른 실무적 시사점을 도출하고자 한다.

This study aims to examine the interest accrual on the delinquency of payment which is frequently occurred in international trade, in the light of the Black Letter Rule, the official comment of the CISG(United Nations Convention on Contracts for the International Sale of Goods) Advisory Council. This study will look primarily at preconditions and interest calculation of delinquency in detail based on the interpretation of Article 78 and Article 78, then it will look at the remaining rules to define interest rates and the various approaches, evaluations and proposals in customs and regulations in accordance with Article 78. Furthermore, it will investigate the compound interest rate, payment method, and defense against interest claims, suspension of interest claim, interest for additional loss, charges and fees for proof. In addition, it will examine existing practices and theories about interest rates in related to interest payment, then review and cross-check with the official opinions of the CISG Advisory Council, and redefine the principles related to interest rates in interest payments and ultimately to find out practical implications. In conclusion, it will propose the implications to the trade industry found in this paper that are drawn from the 12 proposals of the Black Letter Rule as follows: (1) At the time of signing the contract, the parties shall be in compliance with the CISG Article 78 and general principles in Clause 2, Article 7 that is the basis thereof. (2) The parties should apply two different approaches in practice to the determination of interest payments,which reflects the concept of return as set forth in Article 84 whereas similar principles and remedies for damages as set forth in Article 84. (3) Interest shall be incurred from the moment the sum is overdue and the liability for payment of purchase price and recourse claim, and damages shall be incurred and paid upon the occurrence of the damages and/or loss. (4) A monetary obligation that is settled and or cleared or has no liquidity may incur interest. (5) In line with Article 59, there should be prerequisite for interest accrual that include additional requirements such as requests or demand for interest payment or compliance with default or its procedures. (6) When the obligation for payment is cleared, there will be no longer interest accrual. (7) The interest rate may be determined by agreement between the parties, and in case that such agreement is not made, applicable interest rates shall be applied to the statutory interest by the decision of the court in a creditor"s business location in a similar sales contract that is not applied by the CISG. If the same payment procedure is applied, the same amount as the principal will be adhered. (8) The loss suffered by the creditor who cannot recover as interest shall be resolved by compensation in accordance with Article 74.