The interpretation of international investment treaties

International investment treaties, the number of which has exceeded 3.000 today, have a more unique structure than other types of international treaties, although they are governed by public international law. Investment treaties provide broad substantial rights to investors. It also enables disputes to be resolved between the investor and the host state through investment arbitration. In these treaties, the terms and articles are very general and vague. This makes interpretation difficult and gives investment arbitration courts wide discretion. The difficulties in the interpretation of investment treaties are incomparable with other types of international treaties. In addition, there are significant problems with the interpretation of investment treaties in investment arbitration. These problems are mainly due to the fact that the interpretation rules in international law (Articles 31 and 32 of the Vienna Convention on the Law of Treaties) are not fully implemented. Moreover, the differences in the method followed in the application of the elements of Article 31, which is the general interpretation rule, cause significant interpretation problems. The combination of all these reasons identifies investment law with the concepts of "inconsistent decisions", "fragmentation" and "insolvency". It also makes the legitimacy of investment arbitration questionable.