Bank of China Ltd. more than doubled its money set aside for bad loans as profit growth cooled to the slowest pace in five quarters on weakness in the economy. The nonperforming loans of China’s fourth-largest bank surged to 85.9 billion yuan, the highest in more than five years, as companies struggled with repayments in an economy at risk of the weakest full-year growth since 1990. “The biggest concern for Bank of China is their asset quality,” Chen Xingyu, a Shanghai-based analyst at Phillip Securities Research, said by phone.