The spat over CNOOC is a symptom of the growing unease felt in developed economies, but especially in America, as more and more Chinese companies have looked abroad for expansion and technological know-how. Just days before the CNOOC bid, Haier, a white-goods maker, bid $2.25 billion for Maytag, a troubled American rival. In May IBM finalised the sale of its personal-computer arm to Lenovo, a deal that also raised political hackles in America.