(Bloomberg) -- A 400% jump in the past year has transformed Miniso Group Holding Ltd. into the best-performing stock on the Nasdaq Golden Dragon China Index. Market watchers are now debating if the gains are overdone.Most Read from BloombergCaesars Entertainment Paid Millions to Hackers in AttackCiti Plans Job Cuts as It Revamps Top Management StructureChina Sows Fresh Confusion About Apple With Security RemarksLuxury Cruise Ship Full of Australians Stuck in Greenland ArcticFed on Alert for One