London (CNN Business) The American chief executive of Barclays (BCS), Jes Staley, is being investigated by British regulators in connection with his relationship with disgraced financier Jeffrey Epstein, the bank said on Thursday.

"The relationship between Mr Staley and Mr Epstein was the subject of an enquiry from the Financial Conduct Authority to which the company responded," Barclays said in a statement.

According to the bank, the FCA subsequently launched an investigation into how Staley had characterized the relationship to Barclays, and how the bank then described it to regulators. The focus of the ongoing investigation is whether that relationship was properly disclosed.

The FCA and another regulator, the Bank of England's Prudential Regulation Authority, confirmed in a statement that they are investigating the Barclays CEO. They gave no further detail.

Shares in the bank fell as much as 3.8% on Thursday, before paring losses to trade about 2.5% weaker.

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