Can USDT and USDC be frozen by the issuer?

Yes. Both major dollar stablecoins can be frozen by the company that issues them. Tether can freeze USDT held at an address, and Circle can block an address so its USDC can no longer move. Freezes usually follow a legal order, a law-enforcement request or a sanctions match, and if you receive money at an address that is later frozen, you can't spend or send it.

How Tether freezes USDT

Tether's terms allow it to suspend a user's access, "freeze any Tether Tokens held by you, or terminate your Tether Token Wallet, as required by applicable Law or where Tether, in its sole discretion, determines it is prudent to do so" or where the terms were breached source. The same terms list possible sanctions for prohibited use, including "freezing or confiscation" of tokens and "blacklisting any Digital Tokens Address which holds Tether Tokens" source.

Tether's FAQ adds that it "may also seize and destroy Tether Tokens remotely, in response to demands from government, law enforcement or other authorities" source.

How Circle blocks USDC

Circle calls this "access denial". Its policy says: "When an address is denied access, it can no longer send or receive Circle Stablecoin and all of the Circle Stablecoin controlled by that address is blocked and cannot be transferred on-chain" source.

The policy names the grounds: Circle "will block individual addresses in order to comply with a law, regulation, or legal order from a duly recognized U.S. or French authorized authority" or court, and may also act on urgent law-enforcement requests, sanctions-related government requests and security threats. A block can be lifted once the authority confirms the order no longer applies source. Circle's USDC terms also warn that a holder tied to suspected illegal activity "may forfeit any rights associated with your USDC, including the ability to redeem USDC for USD" source.

What a freeze means for you

• If you receive funds at a frozen address, they arrive but you can't move them. The freeze is on the address, not on the payment.
• If the sender's address is frozen, their transfer simply fails.
• If you are paid by a stranger, remember that issuers act on law-enforcement and court requests you can't see in advance, and a frozen balance is effectively lost to you until the freeze is lifted.
• There is no bank to call. Questions about a freeze go to the issuer, and in practice to the authority that requested it.

Freezes happen on the blockchain itself, so they are public. You can browse them in the freeze ledger of Stablecoin scanner ACHIVX, or by network for Tron and Ethereum. Before you accept or send a large amount, look up the other party's address there.

FAQ

Can my own USDT be frozen if I did nothing wrong?

Tether's terms let it freeze tokens when the law requires it or when it considers it prudent, so it is possible, for example if your address received funds connected to a crime.

Can a frozen address still receive USDC?

No. Circle's policy says a blocked address can no longer send or receive its stablecoins.

Can frozen stablecoins be unfrozen?

Circle may lift a block once the authority confirms the order no longer applies. Tether's terms describe freezing and seizure but don't set out a public unfreeze procedure.

How do I know whether an address is frozen?

Look it up in a stablecoin explorer such as Stablecoin scanner ACHIVX, which shows issuer freezes on the address page.