What happened?
On September 28, the minority (Democratic) staff of the U.S. Senate's Permanent Subcommittee on Investigations released a report describing the role of Tether and its dollar stablecoin USDT in what the document calls "Iranian shadow banking." The Defiant links the report to the work of Senator Richard Blumenthal. CoinDesk reports that the authors describe USDT as a "lifeline" for the Iranian regime.
A stablecoin is a cryptocurrency pegged to the value of another asset, in the case of USDT the U.S. dollar. It is used to transfer value on a blockchain without relying on the traditional banking system, which is exactly the feature the report connects to sanctions evasion.
What figures does the report cite?
The most specific figure came from the Polish outlet BitHub.pl, citing the Senate investigation: of 846 crypto wallets linked to Iran and simultaneously hit by U.S. and Israeli sanctions, 84% conducted all or most of their transactions through USDT.
| Data point | Value | Source |
|---|---|---|
| Tracked wallets linked to Iran and sanctions | 846 | BitHub.pl (per the Senate report) |
| Share of wallets primarily using USDT | 84% | BitHub.pl (per the Senate report) |
| USDT volume frozen with Tether's help in 2026 | approx. $550 million | Tether, per The Defiant |
How did Tether respond?
On the same day the report came out, Tether announced that during 2026 it had helped U.S. authorities freeze approximately $550 million in USDT. According to data cited by The Defiant, these were wallets that authorities identified as linked to Iran's central bank and to sanctions networks.
These two statements sit side by side: the Senate report describes USDT as a tool for evading sanctions, while Tether emphasizes its cooperation with authorities and its ability to freeze addresses. Both can be true at the same time, because freezing happens only after specific wallets are identified.
What is proven and what is not?
What is proven is that the report exists, when it came out and who is behind it, and that Tether publicly announced it helped freeze roughly $550 million. Four independent sources confirm this.
Less certain is exactly how the figures in the report were calculated. From the available sources we do not know the precise methodology for selecting those 846 wallets, the time period over which the 84% share was measured, or the full text of the report itself. It should also be noted that this is a minority (partisan) document from one Senate staff, not a conclusion of the entire subcommittee. Note: CoinDesk referred to the body as the "Permanent Subcommittee on Intelligence," while the context (Senator Blumenthal) points more toward the Permanent Subcommittee on Investigations; we leave the exact name as an open item.
What to watch out for with reports of this kind?
With partisan investigative reports it helps to separate three layers: hard on-chain data (how many wallets, what volume), interpretation (what it means), and policy recommendation (what to do about it). Data on USDT's dominance in sanctioned wallets is not surprising, because USDT is the most liquid stablecoin and is widely used in regions beyond the reach of U.S. banks, including the legal economy. That in itself does not tell us what share of the activity is illegal.
Charliedesk does not give investment advice. We record what happened and flag what we do not yet know. Once the full text of the report is published, along with any official responses from OFAC or Tether with further details, we will update our scoring based on what is actually confirmed.