A. The Plaintiff is a manufacturer of the outer parts of a motor vehicle established on August 18, 1997, whose total assets amounting to approximately KRW 23.9 billion, total liabilities amounting to KRW 19.5 billion, total assets amounting to KRW 22.3 billion, total liabilities amounting to KRW 16.4 billion, and total liabilities amounting to KRW 16.4 billion. The Defendant is a bank established under the Banking Act.

B. The emergence background and structure of a currency option contract 1) an exporter company is to receive export price in foreign currency, such as US$, so it is necessary to avoid and avoid risks arising from exchange rate fluctuations. Accordingly, exporters have traded currency derivatives for exchange hedging. 2) In the past, in order to make exchange hedging, simple futures exchange contracts (in the first place: currency forward: transactions in which currency is to be exchanged on certain terms and conditions at a certain time in the future: the right to purchase at a certain time in the future) or call options such as forward options (the right to sell underlying assets at the exchange rate at a certain time in the future) or put options (the right to sell underlying assets at the exchange rate at a certain time in the future: options that can sell and purchase underlying assets: simple options that are not attached to options that can sell and purchase underlying assets in the future, have been used for exchange or exchange hedging in various forms based on the forward exchange rate fluctuations in the futures market.

In the case where the maturity exchange rate is higher than the exercised exchange rate instead of being guaranteed a higher exchange rate than the simple forward exchange rate, the currency option contract determined by put put option contract at a certain multiple of put option contract amount when the maturity exchange rate is higher than the other party's call option contract amount when the other party's call option is held], and for lebreging for rhege: Where the maturity exchange rate is within the upper and lower exchange rate determined in advance, the other party has the right and duty to do so.