Abstract
In recent times, the importance of foreign investments becomes vital in the world’s economy. The mutual cooperation between developed and developing countries by signing the bilateral and multilateral treaties with its own dispute settlement mechanisms is growing significantly. Due to the fact mentioned above, the frame- work gives the possibilities for both - investors and host states to protect their rights in the international forum. The present research is related to the importance of the notion of “Investment” in International Investment Arbitration, its implications, and the current trends on the definition itself. This issue is very important, as it is a threshold jurisdictional question for the International Investment Tribunal’s jurisdiction. The paper discusses the Bilateral Investment Treaties, their legal nature, and the expediency of their conclusion. The issue of Notion of direct investment in bilateral investment treaties will also be detailed in the paper, moreover, there will be an overview of different types of BIT definitions on the example of different countries’ BIT practice. A very comprehensive discussion will be followed on the best practices established by the International Investment Tribunals regarding the definition of “investment”. In the end, the author will analyze whether or not there is a common/universal notion of investment in Investor-State disputes.