채무불이행손해의 산정기준으로서 이행이익과 신뢰이익

Damage incurred to the creditor due to the debtor’s default is computed by calculating ordinary damage, adding special damage, and going through the steps of comparative negligence, offset of profit, limitation of liability and deducting intermediate interest sequentially. However, since the concept of ordinary damage is also abstract, specific calculation standards are required. As a result of reviewing the calculation standards of default damage considering the reality of today’s transactions, where transactions aimed at the use and profit of contract objects such as lease agreement and license agreement are frequent, “expectation interest and reliance interest” were judged to be the most appropriate criteria for calculating default damage. Expectation interest means the profit that could have been obtained by the creditor if the debtor had fully fulfilled the contract (i.e., without default), and it can be calculated by using contract price, market value (market price), gross profit according to the creditor’s position. Reliance interest means the expenses spent by the creditor because he trusted the debtor’s performance, and the reliance interest is divided into essential expenditure and reliance investment costs. Since essential expenditure is part of the expectation interest and also is the reliance interest, the expectation interest is the upper limit of the reliance interest, and essential expenditure can not be claimed double with the expectation interest. On the other hand, as reliance investment costs are not part of the expectation interest, the expectation interest is not the upper limit of the reliance investment costs, and if the requirements for special damage are met, they can be claimed double with the expectation interest. It is judged that the above research results can be used as a reference in calculating default damage. However, it is difficult to ensure consistency in interpretation because ‘expectation interest damage’ is judged by theories or precedents based on interpretation theory. The basis for ‘reliance interest damage’ is inappropriate because it is judged on the basis of culpa in contrabendo under Article 535 of the Civil Act. Therefore, as it was judged that these problems need to be legislatively supplemented, legislative suggestions were made in Chapter 4 of this study.