The present arbitration arises under the Energy Charter Treaty (“ECT” or the “Treaty”), a multilateral convention whose purpose, according to Article 2 thereof, is to establish a legal framework in order to promote long-term cooperation in the energy sector. In Article 10 of Part III of the ECT, Contracting States undertake the obligation to encourage and create stable, equitable, favorable and transparent conditions for Investments of Investors (as those terms are defined in the ECT — see Annex) of other Contracting States.