OKX has warned customers against transferring cryptocurrency directly from MEXC after rolling out stricter compliance controls in response to a U.S. Treasury order targeting more than $16 billion in alleged illicit transactions processed by the exchange.

The warning followed reports of USDT deposits being frozen for review, including transfers conducted through Ethereum and Tron, two of the most active networks for USDT — the world's largest stablecoin by circulation. OKX founder Star Xu confirmed that the exchange had strengthened its risk controls ahead of the U.S. restrictions taking effect, a move that could affect customers transferring legitimate assets between platforms.

MEXC has rejected suggestions that its operations have been disrupted, maintaining that customer assets remain secure while it reviews the regulatory action.

OKX Freezes MEXC-Linked Deposits Ahead of U.S. Deadline

In a November 7 statement on X, Xu advised users not to send funds directly from MEXC to OKX, acknowledging complaints from customers whose deposits had been flagged as potentially high-risk.

The warning followed a customer complaint involving two USDT deposits of approximately $848.80 and $11.70 that were frozen pending additional verification. For retail users, the flagged amounts — roughly $860 combined — show how even routine-sized transfers can be caught in counterparty de-risking before any rule is formally binding.

Xu explained that OKX was applying compliance standards comparable to those used for financial sanctions, even though the Treasury order is not yet enforceable.

"Please avoid transferring funds directly from MEXC to OKX," he wrote, adding that related accounts could face further investigation.

The company has not disclosed how many deposits have been affected, the total value under review, or how long customers should expect the restrictions to remain in place.

The freezes represent an independent compliance decision by OKX rather than a blanket requirement for cryptocurrency exchanges worldwide to block MEXC-related assets.

MEXC Maintains Normal Operations as Treasury Restrictions Approach

The warning follows the U.S. Treasury's decision on November 6 to restrict MEXC's access to American financial infrastructure. Under FinCEN's enforcement action, announced by the Treasury bureau that enforces U.S. anti-money laundering rules, U.S. financial institutions will be prohibited from processing transfers involving MEXC Global, including cryptocurrency transactions.

The restriction takes effect 30 days after publication in the Federal Register and does not automatically freeze customer assets held on MEXC. Because that clock starts only at publication, the Federal Register filing will effectively set the compliance deadline for U.S. platforms.

FinCEN alleges that the exchange facilitated at least $16 billion in transactions connected to sanctions evasion, cybercrime and other illicit activity between May 2021 and May 2026. The findings include approximately $1.5 billion linked to Russian sanctions evasion, nearly $1 billion involving Iranian cryptocurrency exchanges, and additional activity associated with North Korean financial networks.

MEXC has confirmed that trading and other services remain operational, while announcing an independent review of its anti-money laundering and sanctions controls. The exchange said it intends to engage with FinCEN and other regulators, although it has not announced whether it will legally challenge the order.

MEXC management has also emphasized that the restrictions concern transfers involving U.S. financial institutions rather than an automatic seizure of assets held on the platform.

The developments come amid broader scrutiny of cryptocurrency exchanges over sanctions compliance. U.S. prosecutors are also investigating potential Iran-related transactions involving Binance, highlighting mounting pressure on trading platforms to strengthen their transaction monitoring systems.

For MEXC customers, the immediate concern extends beyond the U.S. market. OKX's decision illustrates how regulatory action in one jurisdiction can prompt other exchanges to restrict transfers before legally mandated deadlines. Users with deposits already under review face uncertainty over release timelines, while additional platforms may independently reassess their exposure to MEXC-linked funds. Key developments to track include the Federal Register publication that starts the 30-day clock, the findings of MEXC's independent controls review, and whether the exchange contests the order.