The biggest weekly drop in global trading sentiment on copper since August makes clear that volatility is back. The 5.8-point drop in the past week on this exclusive index of trading sentiment capturing activity in London, Shanghai and New York puts into reverse the improving trend of recent weeks. "Uncertainty over the future direction of global growth and interest rates is preventing any consistent trends taking hold," said Guy Wolf, the head of market analytics at Marex Spectron. That uncertainty notwithstanding, traders in Shanghai are currently the most positive on the direction of what is arguably the most important metal on the mainland.