Asset blocking: who can freeze your crypto funds

Exchanges, stablecoin issuers, and courts can all restrict access to crypto. Here is who holds that power, why they use it, and what a frozen user can do.

In April 2026, Tether said it froze more than $344 million in USDT across two Tron addresses at the request of US authorities, citing activity tied to unlawful conduct. It did not name Iran. A day later, the US Treasury's Office of Foreign Assets Control, known as OFAC, added two Tron addresses holding a combined $344 million to its sanctions list, tied to the Central Bank of Iran. The order matters, because the freeze and the sanctions listing were separate steps taken by separate parties.

The action sat inside a larger pattern. BlockSec data shows Tether blacklisted 4,163 addresses and froze $1.26 billion in 2025. The same tracker showed more than $514 million frozen across 370 addresses in the 30 days to May 8, 2026, a window that spans the April action. The headline cases involve large wallets and sanctions, but the same mechanics can affect ordinary users, and the result looks identical on a phone screen.

A balance sits exactly where it was yesterday. Bitcoin has not crashed, the exchange has announced no outage, and nothing appears wrong. Then a withdrawal fails, and support says the account is under review without saying when the funds will move again. This is one of the less visible risks of holding crypto on a centralized platform, because access can disappear while the balance stays on screen.

The question that matters is who has the authority to impose a restriction, which rules apply, and what a customer can do about it. A freeze the law requires and a freeze the exchange chooses can produce the same message. They carry very different consequences.

What an asset freeze actually means

Asset blocking restricts the ability to access, transfer, trade, or withdraw digital assets. On a centralized exchange it can cover a whole account or only specific funds and transactions. An exchange may pause withdrawals during identity checks, hold funds linked to a suspected scam, or block property because a sanctions rule requires it. From the user's side these cases look the same, but their legal basis and their remedies differ.

A freeze is not confiscation. Blocking restricts access to property, while confiscation permanently takes assets through a legal process. Whether frozen funds come back depends on the reason for the restriction, the governing law, and the outcome of any investigation or challenge.

Why exchanges freeze assets

Not every freeze has the same source, and the source decides what can be done about it. Some are legal obligations that bind the exchange whatever the customer says. Others are internal decisions the exchange makes under its own rules and risk judgment.

Sanctions are the clearest legal obligation. When OFAC designates a person or lists an address, US persons holding that property must deny access to it and meet reporting requirements. Blocked assets can be released only with OFAC authorization or once the legal prohibition no longer applies. The exchange has no discretion to unfreeze, so completing identity verification does not help, and ordinary customer support cannot reverse the block.

Courts and law enforcement can also order an exchange to preserve funds, block transfers, or hand over records. In those cases the exchange is following legal process and not making its own call, so support staff may be unable to explain or reverse the restriction. The remedy usually runs through the authority or court that issued the order, and through the legal procedure for challenging it.

Internal decisions work differently. Anti money laundering rules require exchanges to monitor, investigate, and report, but they usually leave the choice to restrict a particular account to the exchange's own risk judgment. Under guidance shaped by the Financial Action Task Force, exchanges look at patterns of activity, the origin of funds, and links to addresses tied to known risks. A deposit connected to a reported scam can trigger a review even when the recipient knew nothing about its history. A flag is not proof of wrongdoing, and the hold can end once the exchange is satisfied.

Security systems and platform terms belong in the same internal category. An unfamiliar login, a sudden change to account details, or an unusual withdrawal request can pause activity to stop an attacker from draining the account, and most of those holds clear once the owner secures the account and completes official verification. No real exchange employee needs a password, private key, or recovery phrase to do that. Exchanges also rely on their terms of service for incomplete verification, prohibited activity, or suspected rule breaches. A clause in the terms does not make every freeze lawful, because the exchange's contractual rights still sit alongside applicable law, the custody arrangement, and consumer protections.

Stablecoin issuers can block too

Asset blocking is not limited to exchanges. Tether can blacklist USDT addresses through controls built into the token's smart contract, which stops a flagged address from moving the token. Circle has a comparable blocklist function in the USDC contract. AMLBot's analysis of 2023 to 2025 counted 7,268 blacklisted USDT addresses with about $3.29 billion frozen, against 372 USDC addresses and $109 million, a gap of roughly 30 times in value. AMLBot attributes the difference to approach, with Tether working proactively alongside law enforcement and analytics firms, while Circle responds mainly to court orders and sanctions.

This matters for anyone who assumes a personal wallet is out of reach. Moving funds off an exchange removes the exchange's control but leaves the issuer's control in place. Self custody changes the risk profile without guaranteeing protection from every form of blocking, and it adds risks of its own, since a lost recovery phrase or a malicious transaction can cause permanent loss.

When can a freeze be legal?

No single worldwide rule governs every crypto freeze. The answer depends on the jurisdiction, the exchange's obligations, the customer's agreement, and the facts of the transaction. One question sorts most cases: is the restriction required by law, or is it the exchange's own decision?

A required freeze, such as a sanctions block or a valid court order, binds the platform. Release comes only through the authority that imposed it, either an authorization from the sanctions agency or a ruling from the court. An internal freeze rests on contract terms and the exchange's risk judgment, so the exchange can lift it once satisfied, and its basis can be questioned. Whether it is justified and proportionate turns on the facts, the terms the customer accepted, and local consumer protections.

Jurisdiction adds another layer. A user may live in one country, hold assets on a platform registered in another, and face an order issued in a third. A restriction that is lawful under one legal system may be treated differently under another, and a complaint to an authority with no power over the platform will not release any funds. A frozen account proves nothing by itself, because it neither shows that the customer did something wrong nor that the exchange acted unlawfully.

What users can do when assets are frozen

The first step is to find out exactly what is restricted: the whole account, withdrawals only, one transaction, or one token. The notification may point to identity checks, a security review, a compliance investigation, or a legal order. Users should ask the exchange through its official channels which assets are affected, what information it needs, and whether a review process exists, then request a case number. The most useful question is whether the restriction is legally required or an internal review, because the answer decides whether to send documents or to seek legal advice. Keeping copies of every message and the date of each exchange creates a record that matters later.

Evidence of where the funds came from often decides the outcome of an internal review. Transaction hashes, wallet addresses, deposit histories, bank statements, payment receipts, and records of legitimate sales all help, and they should go through the platform's official verification channel. Records must be accurate and unaltered, because an explanation that cannot be supported does more harm than an honest gap.

If support stalls, the next step is the formal complaints or appeals process, with a factual written request that names the transactions involved and asks for a written reply. Beyond that, a financial regulator, consumer protection body, or dispute resolution service may be the right door, depending on the platform and the jurisdiction. Where a freeze rests on a court order or a sanctions decision, a lawyer who knows digital assets and the relevant jurisdiction is more useful than another support ticket. Anyone promising guaranteed recovery for an upfront fee, a seed phrase, or remote access to a wallet is a scammer, and freezes attract plenty of them.

Can users prevent a freeze?

Nothing guarantees that an account will never be restricted, since platforms must respond to security incidents, suspicious transactions, and legal orders however carefully a customer behaves. Good records still make a review easier to survive. Users should save transaction histories instead of relying on the exchange to keep them, document the origin of significant deposits, keep verification details current, and use strong authentication on both the exchange and the email account behind it. Holding only what is needed on a platform, and spreading the rest across more than one setup, limits what a single block can reach.

The trade off behind asset blocking

Exchanges face a real compliance problem. They must detect suspicious activity, answer lawful orders, and protect customers from fraud, and ignoring those duties invites enforcement and lets criminal proceeds move through their platforms. Restrictions also land on innocent users, who can lose access to savings or money meant for an urgent payment while explanations stay vague and appeals drag on. The useful standard is accountability: a clear basis for each restriction, a way to submit evidence, and a real route to review where the law allows one.

The rulebook is still unsettled. Illicit finance was one of the open fights when the CLARITY Act stalled in the Senate in September. Until lawmakers settle who writes the rules, the practical limits on blocking will keep coming from regulators, courts, and the companies themselves.

For crypto users, ownership is only part of the story. Access depends on who holds the keys, who runs the platform, what a stablecoin's code allows, and which laws apply. Learning those layers before depositing funds is far easier than learning them after a withdrawal fails.

Informational material, not legal or investment advice. Rules differ by jurisdiction, and a specific case needs the terms of the platform that applies to it.