China National Petroleum Corp (CNPC) is attempting to revive a failed bid for the Argentinian unit of Spanish energy firm Repsol-YPF in a deal that could be worth up to US$17 billion, the South China Morning Post reported. CNPC may attempt to buy up to three-quarters of YPF, while rival CNOOC is said to be interested in buying a 25% stake. This has prompted fears in Buenos Aires that Argentina’s largest company would be taken over by China; the bid is expected to face political opposition. YPF is Argentina’s largest oil producer and is responsible for about 37% of the country’s output. YPF was bought by Madrid-based Repsol for US$13.4 billion in 1999. Representatives from the Chinese firms declined to comment. In 2007, CNPC twice failed to buy YPF’s Latin American assets.