Sources close to the matter told Financial Times that its German unit, HypoVereinsbank (HVB), was being investigated by the New York County District Attorney’s Office, the US Department of Justice and the US Treasury Department’s Office of Foreign Assets Control.

HVB was acquired by UniCredit in 2005, which is currently operated as UniCredit Bank AG.

As per UniCredit’s prospectus for a capital increase published in January 2012, "A member of the UniCredit Group is currently responding to a third-party witness subpoena from the New York County District Attorney’s Office in connection with an ongoing investigation regarding certain, persons and/or entities believed to have engaged in sanctionable conduct."

"It is not possible at this time to predict the outcome of the ongoing investigation, including the timing and any potential financial impact it may have upon the operating results of the company in any future financial period," UniCredit added.

The lists of other banks accused over similar breaching of Iran sanctions include HSBC, Standard Chartered, Barclays, and Royal bank of Scotland.