IRAN SANCTIONS: HOW WASHINGTON CAN ISOLATE AN ECONOMY

Rubric: INVESTIGATIONS
Format: Investigative Special Report
Author: Sinisa Brkic (sb) / Redaktion

Washington’s new pressure campaign against Iran is aimed far beyond Tehran. Its real targets include the foreign banks, refiners, shipping companies, insurers, brokers, technology suppliers and digital-asset networks that keep Iran connected to the world economy. This report examines how secondary sanctions work, why access to the dollar gives the United States extraordinary leverage, how Iran has learned to route oil and money around restrictions, where China and the Gulf fit into the system, and where the legal and geopolitical limits of American economic power begin.

The target is no longer only Iran

The most important fact about Washington’s latest Iran sanctions campaign is easy to miss. The United States is not merely imposing additional restrictions on Iranian companies and officials. It is trying to change the behavior of companies and financial institutions that are not Iranian and, in many cases, are not American.

On August 24 and 25, 2026, the U.S. Treasury widened its pressure campaign and warned governments, banks and businesses that continued economic ties with Iran could expose them to secondary sanctions. Nearly 60 Iran-linked individuals, entities and vessels were targeted in the opening measures, covering oil, shipping, aviation, technology, military procurement, cyber activity and digital assets. Treasury Secretary Scott Bessent presented the campaign as an effort to cut Iran off from the commercial and financial networks that allow it to earn, move and spend money. The most severe options were not all used immediately. Major Chinese financial institutions, for example, were not included in the first wave. That restraint is important. It demonstrates that sanctions are not an automatic switch. They are a ladder of escalating financial consequences, and Washington can decide how quickly to climb it.

The central question is therefore not whether the United States can prohibit an American company from doing business with Iran. It clearly can under U.S. law. The more consequential question is how Washington can persuade, pressure or effectively force a bank in Asia, a refinery in China, a shipowner in the Gulf or a trading company in another jurisdiction to make the same choice.

Primary sanctions and secondary sanctions are not the same thing

U.S. sanctions are often described as though they form one legal prohibition applying everywhere. They do not. Primary sanctions generally bind U.S. persons and transactions within U.S. jurisdiction. Depending on the relevant program, this can include U.S. citizens and permanent residents, entities organized under U.S. law, persons physically in the United States and transactions involving U.S. property or the U.S. financial system. Iranian property or designated persons may be blocked, and U.S. persons may be prohibited from providing goods, services or financing.

Secondary sanctions operate differently. They are designed to influence certain conduct by non-U.S. persons even when the underlying transaction may have no ordinary U.S. jurisdictional connection. Rather than necessarily declaring the foreign transaction itself unlawful everywhere, the United States can threaten consequences within its own jurisdiction: blocking the foreign actor’s U.S. property, designating it, restricting access to U.S. markets, or cutting a foreign financial institution off from correspondent and payable-through accounts in the United States.

That distinction is legally critical. Washington is not claiming that every foreign company is automatically subject to the same domestic prohibitions as an American company. It is saying, in effect, that certain dealings with Iran can make continued access to the American financial and commercial system conditional. For a large multinational bank or industrial group, that choice can be decisive. The Iranian market may be valuable. Access to dollars, U.S. banks, U.S. investors, American technology and the broader global system built around them is usually more valuable.

The correspondent-account weapon

One of the strongest sanctions tools is also one of the least understood: the correspondent bank account.

Banks cannot maintain full branches in every country and every currency. To move money internationally, they rely on relationships with other banks. A foreign bank that needs to clear U.S. dollars typically requires access, directly or indirectly, to a U.S. correspondent bank. That relationship allows it to settle payments, serve clients engaged in international commerce and participate in the dollar-based financial system.

U.S. law gives Treasury the ability under specified Iran-related authorities to prohibit or impose strict conditions on the opening or maintenance of correspondent or payable-through accounts for foreign financial institutions that knowingly facilitate certain significant transactions.

The practical consequence can be enormous. A bank excluded from dollar clearing is not merely losing access to American customers. It can become less useful to clients around the world. Commodity traders, airlines, manufacturers, shipping companies and multinational groups frequently need dollars even when neither buyer nor seller is American.

This is one of the foundations of secondary-sanctions power. The United States controls access to a financial infrastructure that foreign institutions voluntarily depend on. The threat is therefore not simply a fine. It can be partial exclusion from the plumbing of global commerce.

What counts as a significant transaction?

Secondary sanctions are not supposed to be triggered by a single universal dollar threshold. OFAC guidance describes significance through a totality-of-the-circumstances analysis. Relevant factors can include the size, number and frequency of transactions; their nature and commercial purpose; management awareness; whether the conduct forms part of a pattern; the relationship to blocked persons; the effect on U.S. sanctions objectives; and whether deceptive practices were used.

This matters because sanctions compliance is not reducible to a spreadsheet rule saying that a transaction below a fixed amount is safe. A series of smaller transactions designed to conceal a larger relationship can be more problematic than an isolated payment. Deliberate falsification, shell companies or attempts to disguise Iranian origin can increase risk.

It also means that banks must make judgments under uncertainty. They frequently respond by becoming more conservative than the law strictly requires, a phenomenon often called over-compliance or de-risking. If the commercial benefit of an Iran-related transaction is small and the possible U.S. consequence is catastrophic, compliance departments may reject the transaction even where an exemption or lawful pathway might exist.

Why the dollar matters even when trade is not priced in dollars

Iran and its trading partners have spent years trying to reduce dependence on the U.S. dollar. Payments can be made in Chinese yuan, local currencies, barter arrangements, commodities or digital assets. None of those methods automatically eliminates U.S. leverage.

A transaction may still touch a designated bank, vessel, company or person. A foreign bank may still need U.S. correspondent access for unrelated business. A shipping company may depend on Western insurers. A manufacturer may rely on U.S.-origin technology. A multinational may have American shareholders or subsidiaries. A commodity trader may require financing from institutions that apply U.S. sanctions standards globally. This is why sanctions power is better understood as a network than as a currency rule. The dollar is the most powerful node, but technology, insurance, securities markets, banking relationships, shipping services and corporate ownership create additional points of leverage. Iran’s response has been to build parallel networks specifically designed to reduce those dependencies.

The system was built over decades

The U.S. sanctions relationship with Iran did not begin with the nuclear dispute. After the 1979 Iranian Revolution and the seizure of the U.S. embassy in Tehran, President Jimmy Carter blocked Iranian government property in the United States. Additional restrictions followed. Over the next four decades, sanctions expanded in response to terrorism allegations, regional activity, nuclear proliferation, ballistic missiles, human-rights abuses and other U.S. national-security concerns.

The Iran Sanctions Act of 1996 was a major development because it sought to penalize significant foreign investment in Iran’s energy sector. Later legislation, including measures adopted around 2010 to 2013, greatly strengthened the secondary-sanctions architecture and targeted Iran’s banking, oil, shipping, insurance and other sectors. By the early 2010s, the combination of U.S. sanctions, European measures and international pressure had significantly constrained Iran’s oil exports and access to finance. Those conditions helped create the economic environment in which nuclear negotiations became possible.

The JCPOA demonstrated both the power and the weakness of sanctions

The 2015 Joint Comprehensive Plan of Action was built around an exchange: Iran accepted restrictions and monitoring of its nuclear program, while the United States, European Union and United Nations provided substantial sanctions relief. Implementation in 2016 allowed Iran to reconnect with parts of the global economy. Oil exports increased and previously restricted financial relationships became possible. Yet many international banks remained cautious because U.S. sanctions unrelated to the nuclear issue were still in force and the political durability of the agreement was uncertain.

In May 2018, President Donald Trump withdrew the United States from the JCPOA and reimposed nuclear-related sanctions. Iran later began exceeding nuclear limits in the agreement. By 2025, United Nations sanctions had also returned, and by 2026 the JCPOA was effectively defunct.

The episode contains a central lesson. Sanctions can create negotiating leverage, but relief must also be credible if sanctions are to function as bargaining instruments. If companies believe relief can disappear rapidly after a political change in Washington, they may remain reluctant to return even when restrictions are formally lifted. That makes sanctions easier to impose than to unwind.

Maximum pressure returned

Trump’s return to office brought a renewed maximum-pressure strategy. The administration directed agencies to intensify efforts against Iran’s oil exports, military procurement, financial networks and access to foreign currency. By 2026, the pressure campaign had expanded substantially. Treasury actions targeted Chinese and Hong Kong companies, Gulf-based trading networks, vessels, aviation intermediaries, crypto exchanges and procurement channels linked by U.S. authorities to the Islamic Revolutionary Guard Corps and other sanctioned Iranian institutions.

The August campaign goes further in its political message. Foreign governments and businesses are being told that the cost of maintaining broad commercial ties with Iran may rise sharply. Yet the first wave also exposed the limits of escalation. Washington avoided immediately sanctioning some of the largest financial actors that could cause wider disruption, particularly in China. The reason is straightforward: sanctions powerful enough to hurt Iran can also hurt U.S. strategic interests, energy markets, allies and the international financial system.

Oil remains the center of gravity

Iran possesses one asset that sanctions cannot make irrelevant: hydrocarbons. Oil exports generate foreign currency, support the state budget and connect Iran to major Asian buyers. For years, China has been the dominant destination for Iranian crude. Before the latest conflict-driven disruption, Chinese buyers were taking the overwhelming majority of Iran’s seaborne oil exports.

Independent Chinese refiners, often called teapot refineries, have been especially important. Their business model can tolerate risks that larger state-owned groups may avoid, particularly when Iranian crude is available at a substantial discount.

Treasury has increasingly targeted these refineries and the companies that service them. In April 2026, OFAC warned financial institutions specifically about sanctions risks connected with Chinese teapot refineries, noting the use of front companies, intermediaries, ship-to-ship transfers, falsified documentation and vessel-identity manipulation. The August pressure campaign therefore does not begin with a blank sheet. Washington has already spent years mapping the supply chain.

China is the decisive test

If secondary sanctions are the weapon, China is the hardest target. China has been Iran’s largest oil customer and has repeatedly rejected unilateral U.S. sanctions that are not based on United Nations mandates. Chinese purchases have allowed Tehran to maintain an export outlet even when Western companies withdrew.

The trade has adapted. Iranian crude can be re-labelled in documentation as originating elsewhere. Cargoes can be transferred between vessels. Smaller independent refiners can purchase oil through intermediaries rather than directly from Iranian state companies. Payments can be settled outside the dollar system. Reuters reported in August that Chinese independent refiners remained the core buyers and that Iranian barrels had at times been presented as Malaysian or Indonesian origin. Major Chinese state refiners have generally been more cautious because their international exposure makes U.S. sanctions risk harder to absorb.

This creates a strategic hierarchy. Sanctioning a small intermediary is relatively inexpensive for Washington. Sanctioning a major Chinese bank would be a much larger decision because it could affect global trade and the wider U.S.-China relationship. The ultimate credibility of the new campaign may therefore depend on whether Washington is prepared to move from peripheral actors toward institutions that are systemically important.

The shadow fleet is not one fleet

The phrase “shadow fleet” suggests a centrally controlled group of clandestine tankers. In reality, the system is more fragmented. It can include aging vessels with opaque ownership, frequent flag changes, shell-company managers, complex insurance arrangements, ship-to-ship transfers and manipulation or temporary disabling of automatic identification systems. Cargo documentation can be altered and beneficial ownership can be obscured through layers of companies registered in multiple jurisdictions.

These techniques are not unique to Iran. Similar methods have been associated with sanctioned oil from Russia and Venezuela. That creates a global market in sanctions-resistant shipping expertise. For enforcement agencies, the challenge is that a tanker is a physical asset that can change name, flag, manager and nominal owner while remaining the same ship. OFAC therefore identifies vessels by International Maritime Organization numbers, which remain attached to the hull throughout its life.

Sanctioning a vessel can make insurance, financing, port access and resale more difficult. It does not make the vessel disappear. The effectiveness of the designation depends on whether ports, insurers, traders and governments enforce the consequences.

Insurance is a quiet pressure point

A tanker cannot operate safely and commercially at global scale without insurance and other maritime services. Protection and indemnity insurance covers major liabilities such as pollution, collision and cargo-related claims. Ports and counterparties may require evidence of adequate cover. Mainstream insurers and reinsurers are deeply integrated into Western financial and regulatory systems.

Sanctioned shipping therefore faces a choice: obtain services from smaller or less transparent providers, operate with weaker coverage, or restructure ownership and documentation in an attempt to regain access. That raises risk for everyone around the vessel. An oil spill or collision involving a poorly insured tanker can become a problem not merely for Iran or a sanctions enforcer but for coastal states, ports and private claimants. Economic warfare can consequently shift risk rather than eliminate trade.

Dubai and the Gulf: geography becomes finance

For decades, the Gulf has been one of Iran’s most important commercial interfaces with the outside world. Dubai in particular developed deep trading links with Iranian merchants, logistics firms and financial intermediaries. Those relationships can support legitimate trade, including food, consumer goods and family commerce. They can also be exploited by sanctions-evasion networks using front companies, re-exports, exchange houses and complex payment chains.

The latest pressure has already affected regional commerce. India’s trade with Iran, much of which involved humanitarian goods and Dubai-based payment or logistics channels, has been disrupted by tighter restrictions and the UAE’s halt to certain transactions. This illustrates a recurring sanctions problem: measures aimed at the Iranian state can propagate through third-country trading hubs and affect businesses selling rice, tea, pharmaceuticals or other non-strategic goods. Humanitarian exemptions may exist in law, but banking and shipping risk can still make permitted trade commercially difficult.

The $4 billion crypto and gambling network

Iran’s sanctions-evasion infrastructure is no longer confined to banks, tankers and commodity traders. A Reuters investigation published in July 2026 traced at least $4 billion in cryptocurrency through Shelbit, an unlicensed Dubai-based exchange linked to a sprawling Persian-language online gambling ecosystem. The investigation found interactions between Shelbit and Iran’s central bank as well as addresses linked by Israeli authorities to the IRGC. Reuters also reported that more than 2,000 gambling websites were connected through the network.

The investigation did not establish that every dollar moving through Shelbit belonged to the Iranian government, nor did it establish that every promoter or user knew of state-linked activity. Individuals associated with the gambling sites denied knowledge of Iranian state involvement, and Shelbit later denied knowingly participating in money laundering, terrorist financing, illegal gambling or sanctions evasion.

The regulatory consequences were nevertheless significant. Dubai’s Virtual Assets Regulatory Authority took enforcement action against Shelbit, and in August the U.S. Treasury sanctioned the exchange and its founder, alleging support for the IRGC and other sanctioned Iranian actors. The episode shows why crypto matters to sanctions enforcement. Digital assets can move rapidly across borders without correspondent banks, but public blockchains also create transaction records that investigators can analyze years later.

Crypto is not invisible money

Cryptocurrency is often described as a perfect sanctions-evasion tool. That is only partly true. A blockchain transfer can bypass the traditional banking system, and wallet addresses can be created without the formal onboarding procedures of a regulated bank. Stablecoins can provide dollar-like value without holding a conventional U.S. bank account.

But most major blockchains are transparent. Once investigators attribute a wallet to a sanctioned actor, they can follow flows across thousands of transactions. Exchanges that convert crypto into conventional currency create another enforcement point. Stablecoin issuers may also have technical or legal mechanisms to freeze assets under certain circumstances. Iran’s crypto activity has grown sharply. Reuters reported earlier in 2026 that estimates of Iranian crypto transactions in 2025 ranged into the billions of dollars, with analysts disagreeing over the share attributable to state-linked actors versus ordinary Iranians seeking protection from inflation and currency depreciation.

That distinction is crucial. Crypto is used both by sanctioned institutions and by citizens whose savings are damaged by the same economic isolation. Treating all Iranian crypto activity as state sanctions evasion would be factually wrong.

Front companies are the connective tissue

Sanctions evasion often depends less on sophisticated technology than on corporate opacity. A front company can purchase equipment, charter a vessel, open a bank account or issue an invoice without placing an Iranian sanctioned entity’s name on the document. Networks can move through Hong Kong, mainland China, the UAE, Turkey, Oman, Iraq and other jurisdictions.

The structure may involve several layers. One company buys a commodity. Another arranges freight. A third receives payment. A fourth supplies components. Beneficial owners may be obscured behind nominees or holding companies. For compliance departments, this creates the difficult task of identifying not merely who appears on an invoice but who ultimately owns, controls or benefits from the transaction.

OFAC’s 50 Percent Rule adds another dimension: entities owned 50 percent or more, directly or indirectly and in the aggregate, by blocked persons are themselves treated as blocked even if they do not appear by name on the sanctions list. That forces banks and companies to investigate ownership rather than rely solely on list screening.

Gold, barter and commodities

When access to money is restricted, trade can revert to older forms. Gold can store value outside conventional bank accounts. Commodities can be exchanged through offset arrangements. A country purchasing Iranian goods may leave proceeds in restricted local accounts that Iran can use to buy permitted products from the same country. Barter can replace direct payment.

These systems are less efficient than open banking. That inefficiency is part of the sanctions effect. Iran may still sell oil, but at a discount. It may still import goods, but through longer chains with higher commissions, freight costs and legal risk. Sanctions therefore do not need to reduce trade to zero to impose economic damage. They can function as a tax on every stage of commerce.

A sanctions economy creates its own winners

Economic isolation does not affect every Iranian equally. Companies and institutions with privileged access to foreign currency, smuggling routes, state licenses and political protection can gain market power when ordinary competitors lose access. The IRGC and entities linked to it have long been described by Western governments and analysts as major participants in sectors of Iran’s formal and informal economy.

Sanctions can therefore create a paradox. Measures intended to weaken powerful state institutions may also increase their control over scarce channels for trade. Ordinary businesses without political connections can struggle to obtain banking, insurance and imports. Consumers face inflation and currency depreciation. Well-connected networks can charge premiums for solving the very problems sanctions create. This does not mean sanctions have no effect on the state. It means the distribution of that effect matters.

What sanctions have done to Iran’s economy

Decades of sanctions are not the only cause of Iran’s economic problems. Domestic policy, corruption, structural inefficiencies, political uncertainty and regional conflict also matter. Economic research nevertheless finds substantial sanctions effects. Restrictions can weaken the rial, raise inflation, reduce investment, limit access to technology and constrain growth. Oil revenue is particularly important because it supplies foreign exchange that supports imports and government finances.

The latest conflict and blockade have intensified those pressures. Reuters reported that Iranian oil shipments had fallen sharply by August 2026 compared with the 2025 average, while available cargoes in Asia became scarcer. But Iran has repeatedly demonstrated that economic pain does not automatically produce the political outcome Washington wants. Governments can adapt, repress dissent, shift costs onto households and deepen ties with alternative partners. Economic damage and strategic compliance are not the same thing.

The European legal contradiction

U.S. secondary sanctions create a particularly uncomfortable problem for European companies. The European Union maintains a Blocking Statute intended to protect EU operators from the extraterritorial effects of certain foreign sanctions laws. The regulation can prohibit EU persons from complying with listed foreign requirements unless authorization is granted, and it provides mechanisms related to damages caused by extraterritorial sanctions. The theory is an assertion of European legal sovereignty: Washington should not be able to dictate lawful European commerce simply by threatening foreign companies.

The commercial reality is harder. A European multinational may simultaneously face European rules discouraging compliance with certain U.S. extraterritorial sanctions and an American sanctions regime capable of threatening access to the U.S. market and banking system. After the U.S. withdrawal from the JCPOA in 2018, many European businesses nevertheless left Iran. That outcome demonstrated the imbalance between legal objection and economic exposure. Secondary sanctions are powerful partly because a company can comply without saying sanctions are the reason. It may cite commercial risk, financing difficulties, insurance, contractual terms or strategic priorities instead.

Are secondary sanctions legal under international law?

There is no single global court ruling that makes the entire U.S. secondary-sanctions system either universally lawful or universally unlawful. The United States grounds its measures in domestic statutes and executive authorities and argues that it is entitled to control access to its own financial system, property and markets. From that perspective, a foreign bank has no unconditional right to maintain a correspondent account in New York.

Critics, including governments affected by secondary sanctions, characterize some measures as unlawful extraterritorial coercion because they seek to influence transactions between non-U.S. parties occurring outside U.S. territory. The European Union’s Blocking Statute reflects that objection to specified extraterritorial measures. The legal analysis therefore depends on the specific sanction, the jurisdictional connection, treaty obligations, domestic law in the affected country and the particular consequence imposed. It would be inaccurate to state simply that secondary sanctions are illegal. It would be equally inaccurate to suggest that their extraterritorial reach is internationally uncontested.

Sanctions are not SWIFT

Another common misconception is that the United States controls SWIFT. SWIFT is a Belgium-based cooperative providing secure financial messaging. It does not itself move the underlying money, and it is not an American government agency. European and international legal decisions can affect which institutions it serves.

The United States nevertheless has enormous indirect influence because sanctioned banks may become unusable to counterparties even if messaging remains technically possible. Dollar clearing, correspondent accounts and the risk policies of global banks matter independently of SWIFT access. Cutting a bank from SWIFT can be highly disruptive, but it is only one layer of financial isolation. A bank can lose effective access to global finance without a single universal switch being thrown.

Humanitarian trade is the sanctions system’s moral stress test

U.S. sanctions contain exemptions and authorizations intended to preserve humanitarian trade, including food, agricultural goods, medicine and medical devices under specified conditions. Yet formal legality does not guarantee practical availability. A bank may refuse to process an otherwise permitted payment because it fears hidden sanctions exposure. A shipping company may decline the cargo. An insurer may decide the compliance cost is too high. A supplier may be unable to verify the Iranian customer’s ownership.

This gap between legal exemption and practical access is one of the most persistent criticisms of broad sanctions regimes. Washington has developed humanitarian channels and guidance to reduce the problem, but over-compliance remains difficult to eliminate because private companies bear much of the enforcement risk. A sanctions program can therefore be designed to target a government while still imposing indirect costs on civilians.

Why Washington has not simply sanctioned every Chinese bank

If the United States has the legal tools to impose severe consequences, why not use them immediately against every institution facilitating Iranian commerce? Because sanctions have externalities.

A major Chinese bank can be deeply connected to global trade, U.S. companies and financial markets. Restricting its dollar access could disrupt transactions far beyond Iran. Beijing could retaliate against American companies or financial institutions. Supply chains could be affected. Energy prices could rise. U.S.-China negotiations on unrelated issues could collapse.

The same logic applies to major Gulf institutions and other systemically important actors. This creates what might be called the sanctions escalation problem: the most powerful measures are powerful precisely because the targets are connected to the global system, but those connections mean the damage cannot be confined to the target. The threat can therefore be more useful than immediate execution.

The Strait of Hormuz changes the equation

The current crisis is unusual because financial sanctions are operating alongside severe physical disruption to energy trade.

The Strait of Hormuz is one of the world’s most important oil and gas chokepoints. Conflict, attacks on shipping and restrictions on passage can affect global prices much faster than a conventional sanctions designation. That creates tension inside U.S. strategy. Washington wants to deprive Iran of revenue, but it also wants stable global energy prices. Measures that remove Iranian barrels or frighten shipping can increase costs for consumers and allies. Iran understands this vulnerability. Its geographic position gives it a form of leverage that no banking sanction can erase. Economic isolation is therefore occurring inside a broader contest over physical trade routes.

The difference between isolation and collapse

A country can be isolated from Western finance without being isolated from the world. China, Russia and regional trading partners can provide alternative markets. Informal trade can cross land borders. Local currencies can replace dollars in some transactions. Domestic production can substitute for imports. Smuggling networks can maintain access to critical goods. The price is inefficiency.

Iran pays discounts on exports, premiums on imports and commissions to intermediaries. Capital becomes harder to attract. Technology arrives more slowly. Businesses devote resources to compliance and concealment rather than productivity. That can reduce living standards and state capacity without producing economic collapse. For policymakers, the distinction matters. A strategy built on the assumption that sufficient pressure will automatically cause regime failure may underestimate how long sanctioned economies can survive.

Can Washington truly isolate Iran?

Washington can make normal international business with Iran extraordinarily difficult. It can force globally exposed companies to choose between Iran and access to the United States. It can identify ships, freeze property, threaten banks, target brokers, sanction crypto exchanges and raise the cost of every transaction. What it cannot do by financial authority alone is control every transaction in China, every border crossing in the Middle East, every wallet on a blockchain or every tanker willing to operate outside mainstream insurance.

The practical objective is therefore not perfect isolation. It is attrition: reduce revenue, increase friction, expose networks, make evasion more expensive and force Iran to depend on a smaller number of politically tolerant partners. Whether that produces the desired strategic concession is a separate question.

The real power lies in the choice Washington forces on others

Secondary sanctions are sometimes described as economic warfare. The description captures their coercive nature but can obscure the mechanism. The United States does not need to police every marketplace itself. It makes thousands of banks, insurers, shipping companies, commodity traders, exchanges and manufacturers calculate their own risk. Each institution asks the same question: is the Iranian relationship worth jeopardizing access to the American financial system? Most globally integrated companies answer no.

That decentralized decision-making is what gives sanctions scale. Compliance departments become extensions of the pressure campaign without receiving orders from Washington. Banks terminate relationships before regulators act. Insurers refuse vessels. suppliers cancel contracts. Investors demand explanations. The system works because the United States has something the target values more than the prohibited transaction.

Where the strategy could fail

There are at least five ways an aggressive sanctions strategy can weaken itself. First, excessive use can encourage countries to build alternative payment systems and reduce dollar dependence. That process is slow, but sanctions create an incentive. Second, allies may resist measures they consider extraterritorial or strategically counterproductive. Third, sanctions can strengthen black markets and politically connected intermediaries. Fourth, economic pressure can harm civilians without producing policy change, reducing international legitimacy. Fifth, sanctions can become difficult to trade away. If businesses do not trust that relief will last, a future diplomatic agreement may deliver less economic benefit to Iran than negotiators promise. A sanctions weapon is most valuable when the target believes there is a realistic path to relief.

What to watch next

The first indicator will be whether Washington moves against a major foreign financial institution. The August package deliberately stopped short of the most disruptive options. A designation affecting a large Chinese bank or another systemically important institution would represent a qualitatively different escalation.

The second is Chinese oil behavior. If independent refiners substantially reduce purchases, Washington will have demonstrated that the threat alone is changing commercial decisions. If trade simply migrates into new intermediaries, the campaign will become another contest between enforcement and adaptation. The third is the Gulf. Dubai and other regional hubs are essential to legitimate commerce as well as Iranian sanctions-evasion networks. Stronger enforcement there could close important channels but also disrupt humanitarian and regional trade.

The fourth is crypto. The Shelbit case demonstrated that blockchain networks can move billions outside conventional banking, but it also showed that investigators can reconstruct those flows and turn reporting into enforcement targets. The fifth is diplomacy. Iran says it will resist the pressure while messages about possible talks continue to circulate. If sanctions are intended to produce negotiations, the decisive question is what Washington is prepared to offer in return for Iranian concessions.

The future of economic power

The Iran case is ultimately about more than Iran. For decades, American economic power has rested on an unusual combination: the world’s dominant reserve currency, deep capital markets, globally important banks, technological influence and the willingness of companies everywhere to remain connected to the United States.

Secondary sanctions convert those advantages into geopolitical leverage. But every use of that leverage creates incentives for others to reduce their dependence on it. China is developing alternative financial infrastructure. Governments increasingly discuss trade in local currencies. Digital assets offer new settlement mechanisms. Regional powers seek strategic autonomy. None currently replicates the scale, liquidity and trust of the dollar-centered system. That is why Washington remains so powerful. The strategic question is whether repeated coercive use of the system preserves that advantage or gradually teaches the rest of the world how to live with less of it.

Conclusion: isolation is a network effect

Iran has survived more than four decades of American sanctions because isolation is never absolute. Oil finds buyers. Money finds intermediaries. Companies change names. Tankers change flags. Payments move through currencies, commodities and digital assets. New networks replace exposed ones. Washington’s answer is to attack the network rather than only the Iranian endpoint.

That is the logic behind secondary sanctions. A Chinese refinery, a Gulf trader, an Asian bank or a crypto exchange may have no political interest in the U.S.-Iran confrontation. But if it becomes economically important to Iran, it can become part of the sanctions battlefield. The United States’ strongest weapon is therefore not the ability to stop every transaction. It is the ability to make participation costly enough that much of the global private sector withdraws voluntarily.

The new 2026 campaign is a test of how far that power can be pushed. If Washington can pressure Iran’s remaining partners without destabilizing energy markets, provoking major retaliation from China or driving alternative financial systems forward, it will demonstrate that the dollar-centered sanctions model remains one of the most powerful instruments in international politics. If it cannot, Iran may reveal the limits of a system that is extraordinarily effective at making commerce difficult, but far less certain at forcing states to change their strategic objectives.

Editorial Note: This report distinguishes between U.S. legal prohibitions, exposure to secondary sanctions and commercial decisions taken independently by banks and companies. Not all trade with Iran is prohibited, and exemptions or authorizations may apply, particularly to humanitarian transactions. Where this report refers to alleged sanctions evasion, illicit financial activity or support for sanctioned entities, those claims are attributed to the relevant authorities, court records or reporting on which they are based. A U.S. sanctions designation, investigation or allegation does not by itself constitute a criminal conviction, and newsmedia.report does not treat it as one.