The United States sanctions regime against Iran operates through a complex legal architecture that has evolved since the 1979 Iranian Revolution. At its core, the system relies on two primary authorities: the International Emergency Economic Powers Act (IEEPA) and various congressional statutes that grant the president broad powers to restrict economic activity with designated countries.

The Office of Foreign Assets Control (OFAC), housed within the Treasury Department, serves as the primary enforcement agency. OFAC maintains the Specially Designated Nationals (SDN) list, which includes Iranian individuals, entities, and sectors subject to asset freezes and transaction prohibitions. This list currently contains over 1,000 Iranian entries, making it nearly impossible for Iranian businesses to access the international financial system.

How Primary Sanctions Target Iran

Primary sanctions directly prohibit US persons—including citizens, residents, and companies—from conducting business with Iran. These restrictions cover virtually all economic sectors, from oil and gas to banking and manufacturing. The sanctions freeze Iranian government assets held in US financial institutions and criminalize most trade relationships.

The reach extends to foreign subsidiaries of US companies, creating what sanctions expert Elizabeth Rosenberg calls "a jurisdictional web that captures far more activity than traditional territorial boundaries would suggest." Even non-US companies must carefully navigate these restrictions when dealing with US-connected transactions, technology, or personnel.

Secondary Sanctions: The Global Enforcement Tool

Secondary sanctions represent the most powerful aspect of the US regime, allowing Washington to penalize foreign companies that conduct business with Iran. These measures target third-country banks, insurers, and trading companies, effectively forcing them to choose between Iranian markets and access to the US financial system.

The SWIFT banking network, which facilitates international wire transfers, has repeatedly disconnected Iranian banks under US pressure. This isolation forces Iranian transactions through alternative, often cumbersome channels that significantly increase costs and reduce efficiency. According to sanctions analyst Esfandyar Batmanghelidj, "Secondary sanctions transform US economic power into global regulatory authority, making American law effectively international law for many practical purposes."

Humanitarian Exceptions and Licensed Activity

Despite their comprehensive nature, US sanctions include humanitarian exceptions for food, medicine, and medical devices. OFAC also issues specific licenses for certain activities, including academic exchanges, journalistic activities, and some commercial transactions deemed in the US national interest.

However, these exceptions face practical limitations. Banks and companies often avoid Iran-related transactions entirely rather than risk compliance violations, creating what experts term "over-compliance." This phenomenon means that even legally permissible humanitarian trade faces significant obstacles in practice.

Enforcement and Penalties

Violations carry severe consequences, including civil penalties up to the greater of $300,000 or twice the transaction value, plus criminal prosecution for willful violations. Recent enforcement actions have resulted in multi-billion dollar settlements, such as the $8.9 billion penalty imposed on BNP Paribas in 2014.

OFAC employs sophisticated monitoring tools, including transaction screening software and intelligence sharing with allied governments, to detect violations. The agency's reach extends globally through correspondent banking relationships that connect foreign banks to the US financial system.

What This Means Today

As Iran continues developing its nuclear program amid stalled diplomatic efforts, US sanctions remain a central tool of American foreign policy. Recent additions target Iran's drone and missile programs, while enforcement actions against sanctions evasion networks demonstrate the regime's continued evolution. Understanding this system is crucial for international businesses, policymakers, and anyone seeking to comprehend how economic statecraft shapes global affairs in an interconnected world.