ChangXin Memory Technologies (CXMT), China’s leading maker of dynamic random-access memory (DRAM) chips, saw its shares close up 466 per cent on their Shanghai trading debut, giving the company a market capitalisation of 3.28 trillion yuan (US$484.6 billion) and making it mainland China’s most valuable onshore listing. The semiconductor champion’s Monday debut saw unprecedented trading volume, with turnover exceeding 140 billion yuan as CXMT became the first mainland-listed stock to cross the...