On April 17, 2003, the International Centre for Settlement of Investment Disputes (“ICSID” or “the Centre”) received a Request for Arbitration (“the Request” or “the first Request”) against the Argentine Republic (“the Respondent” or “Argentina”) from Aguas Argentinas S.A.(“AASA”), Suez, Sociedad General de Aguas de Barcelona S.A. (“AGBAR”), Vivendi Universal S.A. (“Vivendi”) and AWG Group Ltd (“AWG”), (together, “the Claimants”). AASA was a company incorporated in Argentina. Suez, and Vivendi, both incorporated in France, AGBAR, incorporated in Spain, and AWG, incorporated in the United Kingdom, were shareholders in AASA. The Request concerned the Claimants' investments in a concession for water distribution and waste water treatment services in the city of Buenos Aires and some surrounding municipalities and a series of alleged acts and omissions by Argentina, including Argentina's alleged failure or refusal to apply previously agreed adjustments to the tariff calculation and adjustment mechanisms