The U.S. Treasury took action to cut Bank Saderat—one of Iran’s major state-owned banks—off from the U.S. financial system. By removing permissions for certain Iran-related payment processing and broadly prohibiting transactions involving the bank, the U.S. signaled that Iran-related banking risk would be treated as a sanctions-enforcement priority.
The UN Security Council adopted Resolution 1737, starting the first round of UN sanctions tied to Iran’s nuclear program. It required states to restrict nuclear-related trade and freeze assets of designated people and entities, creating an international baseline that later U.S. and EU banking sanctions built upon.
The Security Council unanimously adopted Resolution 1747, expanding and tightening sanctions. It added additional designated entities and reinforced calls for financial vigilance, helping set the stage for more intensive scrutiny of Iran’s banks and their overseas connections.
The U.S. Treasury designated Bank Melli under Executive Order 13382, an authority aimed at freezing assets of weapons-of-mass-destruction (WMD) proliferators and their supporters. This made Bank Melli a key target in financial sanctions, increasing the risk for foreign banks and companies dealing with Iran’s largest commercial bank.
Resolution 1803 added targeted sanctions and explicitly called on states to exercise vigilance in dealings between their financial institutions and Iranian banks, highlighting Bank Melli and Bank Saderat. This strengthened the international legal and political basis for tougher banking controls beyond simple asset freezes.
The Security Council adopted Resolution 1929, the most comprehensive UN sanctions round to that point, expanding measures related to Iran’s proliferation-sensitive activities. It reinforced states’ obligations and encouraged stronger controls to prevent abuse of the international financial system, which U.S. and EU authorities then translated into broader financial and banking restrictions.
The EU adopted Council Decision 2010/413/CFSP to implement UN measures and add EU restrictions, including in the financial sector. This decision became a central legal framework for later EU banking limits and asset freezes connected to Iran’s nuclear program.
The U.S. National Defense Authorization Act for Fiscal Year 2012 included Section 1245, which targeted significant financial transactions with the Central Bank of Iran by threatening restrictions on foreign financial institutions’ access to the U.S. financial system. This increased pressure on non-U.S. banks to reduce Iran-related business in order to avoid U.S. penalties.
The United States issued Executive Order 13599, blocking property under U.S. jurisdiction of the Government of Iran and Iranian financial institutions, including the Central Bank of Iran. This broadened the U.S. blocking approach from selected designations to a wider category rule affecting Iranian banks as a whole under U.S. jurisdiction.
Following an EU Council decision, SWIFT announced it was instructed to stop providing financial messaging services to Iranian financial institutions subject to EU sanctions. Because SWIFT messages are a key tool for banks to communicate payment instructions, the disconnections sharply reduced many Iranian banks’ ability to conduct cross-border transactions through normal banking channels.
The EU adopted Council Regulation (EU) No 267/2012, a directly applicable regulation that consolidated and expanded restrictive measures against Iran, including in the financial sector. By moving from decisions to a binding regulation, the EU made key sanctions rules uniformly enforceable across all Member States.
President Obama signed the Iran Threat Reduction and Syria Human Rights Act of 2012, which strengthened and expanded U.S. sanctions authorities. Among other effects, it increased legal and compliance risks for firms and financial institutions connected to Iran-related transactions and sanctions evasion schemes.
Iran and the E3/EU+3 (China, France, Germany, Russia, the United Kingdom, the United States, and the EU) finalized the Joint Comprehensive Plan of Action (JCPOA). The agreement linked nuclear limits and verification to phased sanctions relief, creating a clear pathway toward easing banking and financial restrictions if Iran met its commitments.
The Security Council unanimously adopted Resolution 2231, endorsing the JCPOA and setting out the UN timetable and mechanisms for terminating prior UN nuclear-related sanctions if Iran complied. This marked the closing transition of the 2006–2015 sanctions-building phase into an implementation-and-relief phase driven by verification and agreed milestones.
US and EU Financial Sanctions on Iran's Banking Sector (2006–2015)