China recorded a US$15.9 billion trade surplus in September, the second highest on record, funneling even more foreign capital into an investment boom the government is trying to slow, Bloomberg reported. The number represents a drop from the US$18.8 billion recorded in August, according to figures from the customs bureau in Beijing. For the first nine months of the year, the country's trade surplus is at US$110 billion, up from last year's US$102 billion. Premier Wen Jiabao has said the soaring trade surplus is a big economic problem for China because it strains ties with the US and Europe and makes efforts to cool the economy more difficult.