Abstract
The ICSID arbitral tribunal shall determine the suitability of investors in accordance with the Article 25 of the ICSID convention and the investment or investor's provisions under the BIT. The eligibility of investors has an important role in establishing jurisdiction under international investment disputes. Therefore, this study draws implications on issues related to investor qualification, focusing on ICSID arbitration. The investor's nationality shall be taken into consideration in determining whether the investor is eligible. The criteria for determining the nationality of a corporate investor include the place of incorporation, main business location, and substantial ownership or control. The criterion of the place of incorporation that is used in a number of BIT have the problem of protecting investors from third countries not involved in the BIT. So, in recent years it is stipulated that the actual economic activity or the main business location as well as the place of incorporation criteria. And this problem is complemented by the denial of benefit clause. When determining whether a local corporation is controlled by foreigner in the host state it considers the shareholding rate, voting rights, and the exercise of managerial rights. There is a tendency to recognize shareholder's right to petition. Thus the same damage should not cause problems such as duplicate repayment or double reimbursement between the shareholders and the company. Unexpected problems can arise if the scope of investments and investors is broadly specified in the BIT. Therefore, it is necessary to clarify the scope of investment to be protected.