How US secondary sanctions target Iran's trading partners

The United States has announced new sanctions against Iran and threatened its trading partners with secondary penalties, aiming to sever Tehran's economic lifelines amid a deadlocked conflict. The campaign targets at least 60 entities across the Middle East, Asia, and Europe. Secondary sanctions penalize countries, companies, or individuals that trade with sanctioned nations like Iran, leveraging US market and financial system access as pressure. The US has used this tool before, including against China and Turkiye under the 2017 CAATSA law, though analysts question its effectiveness. Iran's main trading partners include China, Iraq, the UAE, Turkiye, and India, with China buying 80 percent of Iran's shipped oil in 2025. Experts say US leverage is limited over partners with minimal reliance on American financial systems.