Tether Freezes $550 Million in Iran-Linked USDT as Senate Probe Turns Up the Heat

Tether has put a number on its cooperation with US sanctions enforcement, and the timing is no accident. The stablecoin issuer said on Monday that it has helped freeze nearly $550 million in USDT tied to Iran's central bank and Iranian sanctions networks so far in 2026. The announcement came one day after a Senate report accused USDT of being the backbone of Iran's shadow banking system.

How Much Iran-Linked USDT Did Tether Freeze?

Tether detailed two big actions. In April, it helped US authorities freeze more than $344 million in $USDT sitting in two addresses. The following day, OFAC added those same addresses to its sanctions entry for the Central Bank of Iran, which is itself linked to the IRGC-Qods Force and Hezbollah. In July, the Treasury expanded that designation to four more TRON addresses, and Tether froze more than $130 million across those wallets.

Those two rounds account for more than $474 million. The remaining roughly $75 million came from smaller actions between January and September that Tether did not itemize.

The company also pointed to its longer track record. Working with Israel's National Bureau for Counter Terror Financing, Tether has frozen more than 22 million USDT across over 40 referred cases involving more than 640 addresses. Globally, Tether says its cooperation with law enforcement has led to more than $4.9 billion in frozen assets, including over $2.4 billion connected to US authorities, and that it works with around 340 agencies in 67 countries.

Why Is the US Senate Investigating Tether?

The freeze tally landed as a defence. On Sunday, Democratic investigators on the Senate Permanent Subcommittee on Investigations, led by Senator Richard Blumenthal, released a report alleging that Tether and USDT have become central to Iran's shadow banking system. Among their findings: 84% of 846 crypto wallets sanctioned over ties to Iran had transacted exclusively or almost exclusively in USDT.

Blumenthal referred the findings to Treasury Secretary Scott Bessent and Attorney General Todd Blanche, citing potential violations of US sanctions and the Bank Secrecy Act, and called for a federal probe into Tether's compliance.

CEO Paolo Ardoino pushed back, saying Tether has consistently shown that USDT is not a safe harbour for sanctioned actors, terrorist organisations or criminal networks, and that the DOJ, FBI, Secret Service, HSI and OFAC have repeatedly worked with the company to trace, freeze and recover assets.

How Does This Fit Into the Wider Iran Crackdown?

Tether is one front in a much broader campaign. On August 24, the Treasury launched Operation Economic Outcast, targeting almost 60 Iran-linked entities and naming digital assets as one of five sectors vulnerable to sanctions evasion. Federal prosecutors have filed a civil forfeiture case to seize about $61 million in USDT allegedly derived from Iranian black market oil sales, and Manhattan prosecutors are reportedly examining Binance's handling of Iran-linked trading.