Tether freezes 550 million USDT linked to Iran sanctions networks
Tether, the issuer of the world’s largest stablecoin, USDT, confirmed on September 28, 2026, it had collaborated with U.S. authorities to freeze approximately $550 million in USDT over the past year. These funds were identified as linked to Iran’s central bank and various sanctions networks, demonstrating Tether freezes 550 million in suspicious assets.
This significant disclosure arrived concurrently with a critical report from Senator Richard Blumenthal and the minority staff of the Senate Permanent Subcommittee on Investigations, which cast doubt on Tether’s effectiveness in enforcing sanctions compliance.
Why Tether freezes 550 million in suspicious accounts
The Senate report highlighted that an overwhelming 84% of 846 wallets, previously sanctioned or targeted for seizure due to connections with Iran and its regional proxies, had transacted either exclusively or almost exclusively in USDT. This finding immediately intensified the ongoing debate surrounding the role of stablecoins in illicit finance and the responsibilities of their issuers.
Tether detailed specific freezing actions undertaken throughout 2026, totaling more than half a billion dollars. A substantial portion, over $344 million, was frozen across two distinct addresses in April 2026. On-chain records confirm that these particular addresses were blacklisted by Tether on April 23. The very next day, April 24, the U.S.
Treasury Department’s Office of Foreign Assets Control (OFAC) officially added these two addresses to the Central Bank of Iran’s sanctions entry, further linking them to the Islamic Revolutionary Guard Corps-Qods Force and Hezbollah.
Further actions in July 2026 saw more than $130 million in USDT frozen across four additional Tron wallets. Tether blacklisted these addresses on July 14, a move swiftly followed by OFAC’s own update adding them to the same sanctions list. These freezes effectively prevent the targeted wallets from spending or sending their USDT balances, isolating them from the broader financial system.
Blockchain analytics firm Chainalysis reported in July that freezes connected to the central bank totaled nearly $475 million. While Tether’s latest statement did not provide a detailed reconciliation, its overall figure of $550 million underscores a substantial year-long effort to curb illicit financial flows using its stablecoin.
The company has emphasized its global cooperation with authorities, stating that it has helped freeze over $4.9 billion in assets worldwide through such collaborations.
Senate Report Raises Compliance Concerns
Senator Richard Blumenthal, the Ranking Member of the Senate Permanent Subcommittee on Investigations, and his staff published a report that directly challenged Tether’s sanctions controls. This comprehensive study analyzed wallets identified by OFAC and Israel’s National Bureau for Counter Terror Financing between June 2021 and August 2026.
The report’s assertion that 84% of these Iran-linked wallets primarily used USDT is a stark figure. However, the study explicitly clarified that this percentage reflects the prevalence of USDT within that specific, targeted set of wallets, not its overall share of all Iranian financial transactions, which remain largely opaque.
Crucially, the Senate report alleged instances where Tether was slow to act, sometimes taking weeks to blacklist illicit wallets. In one particularly concerning case, an estimated $34.6 million continued to move through sanctioned wallets even after their official designation. This raises significant questions about the timeliness and efficacy of Tether’s internal compliance mechanisms when faced with rapidly evolving threats.
Tether CEO Paolo Ardoino, while not explicitly naming the Senate report, addressed the broader issue in a company statement. He asserted that “Tether can act when credible information is provided by law enforcement,” framing the company as a responsive partner in global efforts against financial crime.
However, the Senate report noted that Tether had acknowledged a June 4 request for information regarding Iranian shadow banking and sanctions compliance but failed to provide a response by the time the report was published.
The Broader Challenge of Crypto in Sanctions Evasion
The growing concern among U.S. authorities stems from the increasing use of stablecoins like USDT for sanctions evasion. Digital assets offer features such as speed, low transaction costs, and a reduced reliance on traditional financial intermediaries, making them appealing to illicit actors seeking to bypass international restrictions.
Reports indicate a worrying trend: in 2025 alone, sanctioned entities and other illicit actors reportedly received an estimated $141 billion in stablecoin. Disturbingly, the Iranian Revolutionary Guards Corp (IRGC) and its affiliated groups are believed to have received at least $1 billion of these funds between 2023 and 2025.
The U.S. Treasury’s Financial Crimes Enforcement Network (FinCEN) has repeatedly warned about Iran’s use of cryptocurrencies, including U.S. dollar-denominated stablecoins, as a means to circumvent stringent sanctions. This highlights a persistent cat-and-mouse game between regulators and those attempting to exploit the burgeoning digital asset ecosystem.
OFAC has been increasingly active in this space, first including cryptocurrency addresses in its sanctions designations back on November 28, 2018. The agency later published “Sanctions Compliance Guidance for the Virtual Currency Industry” in October 2021, aiming to assist companies in mitigating these complex risks. Entities operating within its jurisdiction are required to block virtual currency belonging to Specially Designated Nationals (SDNs).
Beyond U.S. efforts, Israel’s National Bureau for Counter Terror Financing (NBCTF) has also played a crucial role in identifying and targeting crypto wallet addresses linked to illicit activities. Since 2021, the NBCTF has issued numerous administrative seizure orders, identifying 691 addresses across 26 different orders as of August 2026. This multi-pronged international approach underscores the severity of the threat posed by crypto-enabled sanctions evasion.
Implications for Tether and Stablecoin Regulation
This episode places Tether under renewed scrutiny, intensifying the reputational and regulatory pressures on the stablecoin issuer. As the largest stablecoin by market capitalization, with over $170 billion in circulation as of 2025, Tether