Both Tether and Circle can block an address so the stablecoins in it stop moving. The difference is in the rules. Tether's terms give it broad discretion to freeze, while Circle has published a narrower written policy on when it denies access. The contracts also differ: a blacklisted USDT address can still receive tokens, while a blocked USDC address cannot send or receive.
Tether: broad discretion
Tether's terms let it freeze USDT where the law requires it "or where Tether, in its sole discretion, determines it is prudent to do so".[1] The terms list blacklisting an address that holds Tether tokens among its remedies, alongside freezing tokens and reporting to authorities without notice.[1] A formal dispute under the terms goes to confidential, binding individual arbitration.[1]
In practice, Tether says it follows the US Treasury's SDN sanctions list, has a zero-tolerance policy on criminal use of USDT, and can restrict USDT in wallets linked to illicit activity. In April 2026 it said its cooperation with law enforcement had supported more than 2,300 cases and led to freezes of more than $4.4 billion.[2] These are Tether's own figures.
What the USDT contract does
The USDT contract on Ethereum is public. It has owner-only functions to add an address to a blacklist and to destroy the USDT balance held by a blacklisted address.[3] A blacklisted address cannot send USDT. The code does not stop others sending USDT to it, so new USDT that arrives there is stuck too.[3] The USDT contract on TRON has the same blacklist functions.[4]
"Destroy" means what it says. Those tokens are removed from the supply.[3]
Circle: a written, narrower policy
Circle's USDC Terms reserve the right to block certain USDC addresses. For addresses Circle custodies, it may also freeze the USDC there, temporarily or permanently, if it decides at its sole discretion they may be linked to illegal activity or breach the terms.[5] USDC sent to or received from a blocked address may be frozen and lose its redemption rights.[5]
Circle has also published a separate access denial policy. It says Circle will not deny access to individual addresses except in cases that strictly meet the policy: mainly network security threats, legal orders from US or French authorities, and sanctions. A blocked address can no longer send or receive USDC. Circle may reverse a block once the authority confirms the order has been lifted.[6]
What the USDC contract does
In Circle's open-source USDC contract design, a blacklisted address cannot transfer, mint or burn tokens, and only the "blacklister" role can add addresses to the blacklist.[7]
Side by side
| USDT (Tether) | USDC (Circle) | |
|---|---|---|
| Basis for freezing | Terms: where law requires, or where Tether "in its sole discretion" thinks it prudent[1] | Access denial policy: mainly security threats, US or French legal orders, sanctions[6] |
| Blocked address can send? | No[3] | No[6] |
| Blocked address can receive? | Yes, and new funds are stuck[3] | No[6] |
| Issuer can remove frozen tokens | Yes, "destroy" function on Ethereum[3] | Funds may lose redemption rights[5] |
| Way back | Contact Tether; disputes go to arbitration[1] | Circle may lift a block once the authority confirms the order is lifted[6] |
What the 2025 data shows
We found no full public list of freeze decisions, with reasons, from either issuer. The best public count we found comes from a vendor. The security firm BlockSec counted 4,163 USDT addresses blacklisted in 2025, holding $1.26 billion. Only 150 of them (3.6%) were removed from the list the same year, after a median of 18.2 days. $698 million of the frozen USDT (55.6%) was destroyed.[8]
These are BlockSec's figures, not Tether's, and cover USDT on Ethereum and TRON. They suggest that a USDT blacklisting is rarely reversed. We do not have a comparable count for USDC.
What this means for you
- Neither coin is "unfreezable". Both issuers can stop tokens at an address. Picking one over the other does not remove that risk.
- Policies differ in how much they say. Circle's policy names the grounds. Tether's terms leave more to its discretion, and its announcements describe work with law enforcement and sanctions lists.[2]
- A frozen USDT address keeps catching funds. Because it can still receive, tell anyone who pays you to stop sending to it.
- Nobody else can unfreeze. Only the issuer can change its blacklist. Fee-based "unfreeze" offers are scams.
What to do
- Check an address before you accept stablecoins from it, and check its blacklist status for the right network. See our comparison of USDT freeze checkers.
- If your USDT is frozen, follow the steps in why is my USDT frozen.
- Keep records of where your funds came from.
- For large amounts, talk to a lawyer. This is not legal or investment advice.
General information, not legal or financial advice. Rules differ by country and change; check the linked sources.
Sources
- Tether — Terms of Service (26 Feb 2026). Checked 4 Nov 2026.
- Tether — Tether Supports Freeze of More Than $344 Million in USDT in Coordination with OFAC and U.S. Law Enforcement (23 Apr 2026). Checked 4 Nov 2026.
- Etherscan — Tether USD (USDT) on Ethereum: verified contract code. Checked 4 Nov 2026.
- Tronscan — Tether USD (USDT) on TRON: contract. Checked 4 Nov 2026.
- Circle — USDC Terms (12 Dec 2025). Checked 4 Nov 2026.
- Circle — Circle Stablecoin Access Denial Policy (PDF). Checked 4 Nov 2026.
- Circle (GitHub) — Token design (stablecoin-evm). Checked 4 Nov 2026.
- BlockSec (vendor) — USDT blacklisting in 2025: $1.26B frozen on Ethereum & Tron (30 Jan 2026). Checked 4 Nov 2026.