In Shenzhen, southern China, hundreds of small investors crowded outside the offices of a little-known precious-metals platform called JWR, waving contracts and phone screenshots as police tried to keep order. They were there for their savings following the sharp recent rise in the price of gold. But the company couldn't meet the demand for withdrawals. Within days, local officials said they had formed a task force to investigate “abnormal business operations,” according to the South China