HONG KONG -- When the prospectus for Luckin Coffee's New York listing was published last May, nowhere was it more intensely scrutinized than in the offices of Warburg Pincus, high above Grand Central Station.

All froth: Luckin Coffee, whose store count outstripped Starbucks' in China, claimed high-tech credentials as it expanded rapidly through the country and listed overseas. © Nikkei montage/Source photo by Yuki Kohara
How a Chinese tech darling went from startup wonder to market pariah