Chinese authorities have told the nation’s biggest state-owned firms and banks to start a fresh round of checks on their financial exposure and other links to Ant Group Co., renewing scrutiny of billionaire Jack Ma’s financial empire, according to people familiar with the matter.

Multiple regulators, including the banking watchdog, recently told institutions under their oversight to closely examine all exposure they had to Ant, its subsidiaries and even its shareholders up to January, said the people, asking not to be identified as the matter is private. Those people described this as by far the most thorough and wide-ranging look into deals with Ant and said institutions were told they must report findings back as soon as possible.

It was unclear what triggered the new scrutiny or whether it will lead to any actions or conclusions by regulators, the people said. The National Audit Office is leading the initiative, two of the people said. The China Banking and Insurance Regulatory Commission and the top auditor didn’t immediately respond to requests seeking comment. Ant declined to comment.