This study deals with Investor State Dispute (ISD), which allows foreign investors to sue countries for discriminatory practices. In particular, we focus on the financial issues of the ISD lawsuit filed with the Korean government on the merger of Samsung C&T and Cheil Industries. First, the adequacy of Elliott's claim is assessed by dividing it into two cases: selling shares before the merger and holding them after the merger. First, when the price of stock purchase claim is used as the selling price of Samsung C&T before the merger, stock value exceeds the range suggested by various evaluation agencies before the merger. Second, a net present value model is proposed to calculate the profit or loss of existing shareholders if the stock is held until after the merger. In the model, shareholders' profit and loss is determined by the synergy of the merger and the appropriate merger ratio. Even if we set the consensus range suggested by the agencies at the appropriate merger ratio and assume various merger synergies, the amount of damage did not reach the amount claimed by Elliott.