Treasury Secretary Scott Bessent announced a sweeping campaign to isolate Iran from the global economy, dubbed "Operation Economic Outcast." This initiative aims to close loopholes in existing US financial sanctions and force an "endgame" in the conflict. Bessent warned that countries continuing to do business with Iran could face significant financial repercussions, including losing access to the US financial system, and stated that a "cure period" has begun for compliance. He indicated that the Treasury expects to sanction a major foreign financial institution by the end of the week.

The new measures expand the Treasury Department's ability to penalize foreign companies supporting five sectors of Iran’s economy: digital assets, technology, gold, aviation, and shipping. Additionally, fresh direct sanctions were imposed on numerous Iranian individuals and entities, and waivers permitting remittance payments and access to US cultural and academic institutions for Iranians were ended. However, critics suggest the announcement was largely a "warning shot" rather than an immediate impactful action, noting that its true effect hinges on the US's willingness to impose sanctions on China, which provides an economic lifeline to Iran by purchasing approximately 90% of its oil exports.

Analysts like Ali Vaez of the International Crisis Group expressed skepticism, stating that only the actual execution of threats, not just the threats themselves, would make a difference. Another White House insider suggested the initiative could be impactful if executed, but without addressing China's role, Iran retains an "economic escape route." Despite the announcement, global benchmark Brent futures saw a slight ease, falling around 2.4% on Monday to $92.17 a barrel, though this is still 31% higher than the $70.14 a barrel seen during a brief ceasefire earlier in the year.

Iran's crude oil exports have drastically fallen since February, from an average of 1.75 million barrels per day (bpd) in the three months preceding the US and Israeli attacks to just 255,000 bpd in August, down from 893,000 bpd in July. This August figure is even lower than the 259,000 bpd recorded in May, which was the lowest since May 2020. The uncertainty surrounding Iran's response to these sanctions is expected to maintain a nervous premium on crude oil prices.