Copper is arguably the most important metal to China, so a slide in futures prices from July to October that took the market to a six-month low has been a gripping ride for investors. Sentiment, though still subdued, has rebounded from recent lows, and a fresh 4.2-point gain on the week in this exclusive index of global copper trading sentiment that captures activity in London, Shanghai and New York is another positive. But all the positivity is coming from the United States, according to Guy Wolf, head of market analytics at Marex Spectron. "US economic recovery is gradually overcoming concerns over Chinese demand," he says. More balance might yet be needed to support a sustainable rally.