Secondary sanctions

Secondary sanctions are penalties imposed on third-country persons and firms for dealing with a sanctioned target, extending the sanctioning state's reach beyond its own jurisdiction. Where primary sanctions bind the sanctioning state's own nationals, secondary sanctions confront foreigners with a choice: continue business with the target or retain access to the sanctioning state's market and financial system. Their legality under international law is contested, and they are the principal driver of allied friction over US extraterritoriality.

Mechanism

The instrument works by conditioning access rather than directly extending a primary prohibition. A foreign bank may face a specified correspondent-account sanction, blocking measure or menu sanction if an operative authority covers its transaction. That exposure is distinct from a primary rule binding US persons. It is also distinct from an advisory warning, an actual designation and a bank's voluntary decision to avoid lawful business. Over-compliance can amplify the practical effect as banks de-risk beyond what the rules require (over-compliance), but the private compliance decision does not become a government order.

Legal or institutional basis

The paradigm statutes are the Comprehensive Iran Sanctions, Accountability, and Divestment Act (2010), which threatened foreign banks transacting with designated Iranian entities with loss of US correspondent access; Section 1245 of the National Defense Authorization Act for Fiscal Year 2012, which extended the threat to foreign banks settling specified oil payments with the Central Bank of Iran; and the Countering America's Adversaries Through Sanctions Act (2017), which provides for measures in the Russia programme. Section 311 (USA PATRIOT Act) is legally distinct: it authorises special measures against a jurisdiction, institution, account or transaction found to be of primary money-laundering concern, and can affect third-party access without becoming a secondary sanction.

Employment history

Secondary measures formed one part of the Iran pressure campaign from 2010 to 2015 and were reimposed after the 2018 US withdrawal from the nuclear agreement. Their independent causal effect cannot be separated cleanly from primary sanctions, oil restrictions and diplomatic pressure. In Russia-related programmes after 2022, authorities have used them against specified sanctions-evasion conduct and third-country intermediaries. OFAC FAQ 1182, updated 11 June 2026, states that transactions authorised or exempt under relevant sanctions, including specified humanitarian, agricultural and medical trade, do not create sanctions risk for foreign persons merely because they involve Russia. Current exposure therefore depends on the operative authority, transaction and target, not country contact alone.

Effects and countermeasures

The instrument's reach creates political and compliance costs. The EU blocking statute seeks to protect EU operators from specified extraterritorial measures and permits recovery of certain resulting damages, while also restricting compliance with listed foreign requirements unless authorised. That conflict can leave a multinational facing incompatible legal duties. Banks may respond by abandoning even authorised business, widening the practical effect beyond the operative rule. These reactions can encourage efforts to build alternative payment and settlement channels, but the cited legal sources do not establish the scale or success of that backlash. In Economic Kill Chain terms, secondary sanctions amplify a primary pressure campaign by placing specified third parties at risk of separate measures.

See also

OFAC-style targeted sanctions · Extraterritoriality · Correspondent-account closure · Compliance cascade · Economic statecraft

Sources

• US Comprehensive Iran Sanctions, Accountability, and Divestment Act 2010, accessed 30 July 2026.
• OFAC CAATSA sanctions programme, accessed 30 July 2026.
• OFAC FAQ 1182, updated 11 June 2026, accessed 30 July 2026.
• European Commission Blocking Statute, accessed 30 July 2026.