Global oil company BP PLC is negotiating to buy a stake in China Aviation Oil (Singapore) Corp, the jet-fuel trader that lost more than US$550 million trading oil derivatives last year, the Wall Street Journal reported, citing people familiar with the matter. BP, which is said to be actively seeking a foothold in China, declined to comment. China's state-owned China Aviation Oil Holding Co, the parent company of CAO (Singapore), looks set to sell 25% of the subsidiary valued at US$55 million to multiple investors, which, besides BP, also include Temasek Holdings, Singapore's state-owned investment arm.