U.S. Iran oil sanctions are a set of restrictions under IEEPA and the Iran Freedom and Counter-Proliferation Act that prohibit foreign financial institutions from processing payments for Iranian crude oil purchases. Countries that reduce purchases toward zero can receive temporary exceptions called Significant Reduction Exceptions (SREs). The Trump administration reimposed these sanctions in 2018 after withdrawing from the JCPOA and ended SREs in 2019, aiming for "maximum pressure." The Biden administration maintained most of these restrictions while attempting nuclear negotiations. General licenses, including GL U, can carve out specific transaction windows outside the broader prohibition regime.