키코 통화옵션계약의 공정성에 관한 연구 - 대법원 2013. 9. 26. 선고 2011다53683(본소), 2011다53690(반소) 판결을 중심으로 -

The plaintiff, a machine exporter, entered into KIKO currency option contracts in 2007 with defendant banks under apprehension of a fall in the exchange rate between the U.S. dollar and the Korean won. According to the contracts, the plaintiff gave call option to the banks in exchange for put option offered from them. The plaintiff, who suffered heavy losses on account of a sudden rise in the exchange rate after 2008, brought a suit against the banks for damages and unjust enrichment. The plaintiff argued that the KIKO contracts were unfair to the company and unsuitable to adequately hedge against fluctuations in the exchange rate, and that the banks failed to fully explain the KIKOs and their potential risk. Among the above major controversial arguments, this paper touches upon only the issue of unfairness. The unfairness argument claimed by the plaintiff is that the value of call options the company provided to the banks was highly greater than that of put options the company received. Thus, the KIKO contracts are unfair and unjust under Section 104 of the Korean Civil Law since the payment and the benefit in return for the payment are extremely unbalanced. However, the Korean Supreme Court rejected the plaintiff’s unfairness argument. First, the Court regarded the most part of spread between call options and put options as bank charges. It opined that most bank charges are the credit risk charge and hedge cost, and that the differences between the charge and the cost are not excessive. Second, the Court contended that, if the charge rate for KIKOs was calculated on the basis of call option's dollar amounts, the margin rate of KIKOs was not higher than that of other service charges of banks. Third, the Court concluded that in consideration of potential additional benefits which the plaintiff might have obtained, the margin cannot be regarded as unjust only because of its exceeding discrepancies in the margin between the value of call option and that of put option. This paper examines in detail the Court’s reasoning that the KIKOs are not unfair, and, in case, utilizes some quantitative approaches to prove unfairness of the KIKOs. Finally, it is found that the Court reached a wrong conclusion by misunderstanding the amount of cost, the way to estimate margin rate, and the additional advantages for the plaintiff under the KIKOs.