Mainland Chinese shares are surging back from a sell-off amid regulatory support and huge purchases by state investors and major companies. The CSI 300 index rose 3.1 per cent on Tuesday, following a 1.5 per cent gain on Monday after China Securities Regulatory Commission (CSRC) chairman Wu Qing met industry representatives to discuss market stability. The tech-heavy Star 50 Index skyrocketed 11 per cent. Major insurers and other listed companies also unveiled stock purchases or buy-backs,...