The City watchdog is investigating the hedge fund founded by Crispin Odey as he faces renewed allegations of sexual misconduct.
The Financial Conduct Authority (FCA) was understood to be considering the expansion of an existing inquiry focusing on corporate governance at Odey Asset Management after the Financial Times claimed that he had faced a string of complaints about his behaviour over decades.
Its investigation highlighted allegations of sexual harassment or assault by 13 women against the wealthy fund manager over a 25-year period.
Mr Odey, who is believed to be worth hundreds of millions of pounds, has strenuously denied the paper's claims.
The Reuters news agency, citing sources, said that Wall Street banks JPMorgan and Morgan Stanley were reviewing their prime broking relationships with Odey Asset Management in the wake of the FT report.
Neither bank has commented.
But Mr Odey said of the report: "That is a massively quick reaction to an allegation by the FT.
"This is a rehash of an old article and none of the allegations have been stood up in a courtroom or an investigation."
Mr Odey stepped down as co-CEO of Odey Asset Management during the COVID pandemic but remains a major shareholder.
He was later cleared of indecent assault charges by a UK court in 2021 and told by the judge in the case that he could leave the building with his "good character intact".
It is understood that the 64-year-old, who is a donor to the Conservative Party, has been married three times and has three children.