KWG Group Holdings Ltd. securities tumbled Tuesday after the firm became the latest Chinese developer to default, even as new-home sales gain steam nationally. The company didn't pay 212 million yuan ($31 million) of principal due Friday on bank and other borrowings, it said in a Hong Kong stock exchange filing that night. The delinquency triggered 31.2 billion yuan of debt becoming repayable on demand. KWG's annual report, also filed Friday, said the firm faces multiple uncertainties "which cast significant doubt on the Group's ability to continue as a going concern."