How China Built a Yuan Firewall to Shield Iran and Russia from US Sanctions

Washington’s traditional leverage over adversaries is steadily eroding as Beijing builds a robust financial architecture centered on the yuan.

According to The Wall Street Journal, this parallel system allows heavily sanctioned nations like Iran and Russia to conduct international trade and sell oil largely outside the reach of the U.S. banking sector.

The shift was underscored in late April when the U.S. sanctioned Hengli Petrochemical, a major Chinese refinery, for purchasing Iranian oil.

The company subsequently announced that future oil buys would be settled in yuan rather than the U.S. dollar.

The move reflects a broader strategic pivot by Beijing to facilitate trade beyond Washington's jurisdiction.

Historically, the U.S. dollar's dominance in 80% of international trade finance granted Washington unmatched authority to police global business.

Transactions denominated in dollars require American banking infrastructure, enabling the U.S. to monitor flows and sever access to cripple targeted economies.

By utilizing the yuan, adversaries bypass the U.S.-led banking system entirely.

This dynamic has blunted Washington’s current diplomatic efforts with Tehran, where the promise of unfreezing roughly $100 billion in assets holds less weight than it once did.

Sustaining the Oil Trade

Despite strict U.S. embargoes, Iran generated up to $43 billion in oil revenue in 2024.

Most of these sales were processed in yuan, according to the U.S. Treasury.

Tehran uses these yuan reserves to procure Chinese goods, including vehicle components, solar panels, and dual-use materials with potential military applications.

Iranian and Chinese partners have established clandestine intermediaries and front companies in Hong Kong to facilitate this ongoing trade.

A similar strategy was deployed by Moscow following the outbreak of war in Ukraine in February 2022.

Today, more than 90% of bilateral trade between Russia and China is settled in yuan and rubles, a stark increase from just 2% before the conflict.

Financial Infrastructure Expansion

Much of this illicit activity relies on the Cross-Border Interbank Payment System (CIPS), China’s yuan-denominated alternative to the SWIFT messaging network.

Since its establishment in 2015, CIPS transaction volumes have surged.

Following the onset of the U.S.-Iran conflict, daily network volume averaged $115 billion over three months, up from $100 billion the previous year.

Total daily transactions on CIPS have doubled since the war in Ukraine began. Although Swift still processes over $5 trillion daily, the yuan's share of global trade finance has tripled over the past five years to 6%.

About half of China’s cross-border transactions are now denominated in its native currency.

China is not seeking to replace the dollar entirely worldwide, a move that would require lifting capital controls and risking domestic economic instability.

Instead, Beijing aims to construct specific, insulated trade lanes that undermine U.S. authority and shield allies from Western economic assaults.

Shadow Networks

To maintain plausible deniability, Chinese state-owned oil majors largely avoid Iranian crude.

The trade is instead sustained by private refiners and a shadow fleet of tankers that disable their location-tracking systems to obscure the oil’s origin.

Instead of transferring payments directly to Iran, Chinese buyers park yuan funds with entities like Chuxin.

These intermediaries distribute the capital to Chinese contractors executing engineering projects in Iran.

The mBridge Digital Frontier

Beyond traditional banking, China is rapidly scaling mBridge, a blockchain-based platform launched in 2021 to settle cross-border payments in digital currencies.

The network includes the U.A.E., Thailand, Hong Kong, and Saudi Arabia.

By utilizing digital versions of the yuan, central banks can settle transactions instantly without interacting with U.S. financial institutions.

As of November, the digital yuan accounted for 95% of cross-border payments on the mBridge platform.