China’s securities regulator instructed brokerages on Sunday to review trades and enforce rules that require the use of real names and national identification numbers, the latest move by the government aimed at stabilizing stock prices following a devastating market rout the past month. The latest warning by the China Securities Regulatory Commission (CSRC) is meant to clamp down on a trick whereby a single investor controls multiple accounts — often registered under other people’s identification numbers — to bid the price of a stock up or down.