Alibaba Group Holding Ltd.’s U.S.-traded shares tumbled as much as 9.7 per cent Tuesday after Ant Group Co., the finance affiliate also founded by Jack Ma, said its listings in both Shanghai and Hong Kong have been suspended.

Ant’s listing in Shanghai was halted amid changes in the regulatory environment, according to a statement, which didn’t provide further details. With the initial public offering in Hong Kong also on hold, Ant’s US$35 billion share sale is in limbo.

Alibaba owns about a third of the payments company, which was expected to begin trading on both exchanges on Thursday. Its American depository receipts slumped the most intraday since March 16.

The surprise move in China is stirring questions from investors about whether a broader regulatory shift could be underway. Other Chinese companies that trade in the U.S. also fell Tuesday. JD.com Inc. dropped 1.4 per cent, while Lufax Holding Ltd. slipped eight per cent. IQIYI Inc. declined 1.5 per cent, and LexinFintech Holdings Ltd. was down five per cent.

Ma had antagonized some in China with a speech that accused regulators of restricting innovation. Chinese officials summoned the billionaire and his lieutenants at Ant to a meeting Monday and warned them that the company would face regulatory scrutiny similar to that of banks.

Andrew Left, the founder of Citron Research, said the suspension of Ant’s listing could be an isolated and temporary setback. “Hopefully this is a short-term bump,” he wrote in an email.

--With assistance from Isabelle Lee.