By Notice of Arbitration dated 14 March 2003, EnCana Corporation (“EnCana”) a Canadian corporation, commenced the present proceedings against the Government of the Republic of Ecuador pursuant to Article XIII(2) of the Canada–Ecuador Agreement for the Promotion and Reciprocal Protection of Investments of 29 April 1996 (the BIT).1 The claim concerned measures taken by Ecuador in respect of two wholly–owned EnCana subsidiaries, AEC Ecuador Ltd (previously named City Investing Co Ltd) (AEC) and City Oriente Limited (COL), both incorporated in Barbados. In its Notice EnCana alleged that Ecuador's action (in particular, through resolutions of the tax authorities, the Servicio de Rentas Internas (SRI)) in denying to its subsidiaries refunds of value added tax (VAT) violated provisions of the BIT. It sought declarations to that effect as well as consequential relief, including reimbursement of tax credits denied and which might be denied in future. The value of tax credits already denied was put at approximately US$80m.