Bearish bets against shares of Z. AI Co. and Mini Max Group Inc. have soared to records ahead of their earnings reports, highlighting growing investor worry over China's heated AI rivalry. Short interest has climbed to account for 20% of the free float for Mini Max and 6% for Z.

AI, or Zhipu, according to data from S&P Global. Short selling ramped up even after the Hong Kong-listed stocks tumbled from record highs following the pair's blockbuster listings early this year.