FinCEN issues first subpoena in investigation into Greek bank’s potential Iran connections
The US Treasury's Financial Crimes Enforcement Network has issued its first administrative subpoena under a rarely used banking provision as part of an investigation into a Greek bank's potential connections to Iran and its proxies.
WASHINGTON, Oct. 21, 2026 — The Financial Crimes Enforcement Network (FinCEN) announced the unprecedented use of its administrative subpoena authority under Section 5318(k) of the Bank Secrecy Act, marking a significant development in US efforts to investigate international banking relationships potentially linked to Iranian financial networks.
The subpoena was issued as part of an investigation into a Greek bank's potential connections with Iran and Iranian proxies, conducted in coordination with European authorities. FinCEN did not publicly identify the institution or disclose the specific transactions under investigation. The announcement does not constitute a sanctions designation or establish that the bank violated US law.
Section 5318(k) provides US authorities with powers to obtain records from foreign banks maintaining correspondent accounts in the United States, including certain records held outside US territory. The provision allows investigators to examine international financial activity through foreign banking relationships that intersect with the US financial system. Failure to comply with a qualifying subpoena can result in restrictions on a foreign bank's access to US correspondent banking services.
FinCEN also disclosed that it had issued multiple information requests concerning banking relationships with Iranian financial institutions already designated by the Office of Foreign Assets Control. The investigative activity forms part of Operation Economic Outcast, a broader Treasury initiative aimed at disrupting financial networks supporting Iran's sanctioned activities.
The action highlights the Treasury's use of financial investigative powers alongside traditional sanctions designations, extending scrutiny to foreign financial institutions and their potential role in facilitating transactions connected to Iran. No enforcement penalty, asset freeze or formal finding of wrongdoing against the unidentified Greek bank was announced.