Secondary sanctions are a tool used by the United States to extend the reach of its sanctions programs beyond its direct jurisdiction. They target non-U.S. persons (individuals, entities, or governments) for engaging in specific commercial or financial activities with a primary sanctioned target, even if the transaction itself has no direct connection to the United States. The purpose is to deter foreign actors from undermining U.S. foreign policy objectives by dealing with sanctioned countries or entities, effectively forcing them to choose between doing business with the sanctioned target or with the United States.

A. Sanctions which apply to more than one country: This describes multilateral or comprehensive sanctions, not the specific mechanism of targeting non-jurisdictional persons that defines secondary sanctions.

C. Sanctions which are transferred to a bank through its correspondent banking relationship: This describes a common enforcement vector for sanctions, but it is not the definition of secondary sanctions themselves.

D. When an entity has been sanctioned for the second time: This is an incorrect, literal interpretation of the word "secondary" and does not describe this specific type of sanctions measure.

1. ACAMS Certified Global Sanctions Specialist (CGSS) Study Guide, 6th Edition, Chapter 2: Sanctions Regimes and Their Key Components, Section: "Primary vs. Secondary Sanctions." The guide explains that secondary sanctions are "designed to apply to non-US persons who are outside of US jurisdiction" and are used to "prevent third parties from engaging in trade or other transactions with a sanctioned country."

2. U.S. Department of the Treasury, Office of Foreign Assets Control (OFAC), "Frequently Asked Questions." OFAC's guidance on various programs, such as those related to Iran or Russia, defines secondary sanctions as measures that can be imposed on foreign persons for engaging in certain conduct outside of U.S. jurisdiction. For example, FAQ 563 on Iran states that non-U.S. persons may be exposed to secondary sanctions for certain transactions with Iranian persons.

3. Congressional Research Service (CRS), "U.S. Sanctions: An Overview," Report R45415, (Updated October 22, 2021), page 2. The report defines secondary sanctions as those that "are intended to restrict the economic activity of non-U.S. persons, even when that activity occurs entirely outside U.S. jurisdiction... to dissuade non-U.S. persons from engaging in activities that are contrary to U.S. interests."