Shein Executive Chairman Donald Tang will step down as his mission of taking the company public nears completion, three sources with direct knowledge of the matter said on Monday, retreating to an advisory role after three years as the public face of the global fast-fashion retailer. A Chinese-American billionaire who began his career in banking, Tang has acted as the Western proxy of secretive Shein founder Sky Xu, liaising with politicians and regulators around the world while also...