E-commerce Shein aims to launch its Hong Kong initial public offering on Monday, according to a source familiar with the matter, and is targeting a listing on September 1, two other sources said, slightly later than previously planned. While September 1 is the target date, the listing could happen a few days later, one of the sources said. The delay, first reported by the South China Morning Post, comes as slower growth and rising costs have dampened investor appetite for Shein. The online fast-fashion retailer was seen just a few years ago as a disruptive challenger to established retailers such as H&M and Zara, thanks to its rapid supply chain and ultra-low prices. Among cornerstone investors in the IPO is the asset management arm of UBS Group, which would be investing in Shein for the first time, according to a fourth source with direct knowledge of the matter.