Nils Silinevics
Partner · AML & Crypto Compliance · Former FIU Investigator
You've seen your account restricted pending source-of-funds verification on CEX.IO. CEX.IO, headquartered in United Kingdom (registered with FCA), is regulated by UK Financial Conduct Authority (FCA) under UK Money Laundering, Terrorist Financing and Transfer of Funds Regulations 2017. The exchange uses Chainalysis for blockchain analytics and Onfido for identity verification. CEX.IO is one of the few exchanges FCA-registered as a crypto-asset business in the UK. This means they're subject to UK MLR 2017 — one of the strictest AML regimes — but also means they follow due process more rigorously than offshore exchanges. CEX.IO freezes accounts under UK Money Laundering Regulations when their compliance team detects sanctions matches, high-risk deposits, or unusual withdrawal patterns. You receive an email or in-platform notification asking you to prove where your cryptocurrency came from. The request may include demands for bank statements, pay slips, tax returns, business records, sale contracts, mining proof, or inheritance documents — depending on how you acquired your crypto.
CEX.IO freezes accounts under UK Money Laundering Regulations when their compliance team detects sanctions matches, high-risk deposits, or unusual withdrawal patterns. CEX.IO is one of the few exchanges FCA-registered as a crypto-asset business in the UK. This means they're subject to UK MLR 2017 — one of the strictest AML regimes — but also means they follow due process more rigorously than offshore exchanges. This background matters because it shapes how CEX.IO handles compliance — and how we approach resolving your case.
The compliance framework: CEX.IO operates under UK Money Laundering, Terrorist Financing and Transfer of Funds Regulations 2017, overseen by UK Financial Conduct Authority (FCA). Their compliance infrastructure uses Chainalysis for blockchain analytics and Onfido for identity verification. CEX.IO is known for fiat onboarding and card purchases for beginners, serving entry-level crypto users in Europe and UK — and their compliance team is calibrated to flag deviations from typical user behavior in that segment.
What triggers source of funds request on CEX.IO:
Real case — FCA regulation: A UK-based user had €30,000 frozen on CEX.IO after making a large withdrawal to a new bank account. CEX.IO's compliance team requested source of funds documentation but the user's funds originated from crypto mining 5 years ago — he no longer had the mining records. We reconstructed the mining history from blockchain evidence (pool payouts, hardware purchase receipts) and CEX.IO released the funds within 8 days.
What CEX.IO requires to resolve this: Depending on the trigger, CEX.IO may ask for government-issued photo ID (verified through Onfido), proof of address (utility bill or bank statement within 3 months), AML compliance review (exchange statements, bank records, payslips, tax returns, or business documents), detailed transaction explanations with on-chain evidence, and in some cases a video verification interview. The challenge: CEX.IO rarely tells you which specific trigger caused the source of funds request, so you're guessing at what documentation to provide — and each rejected submission makes the next one harder.
Our approach is specific to CEX.IO: CEX.IO's FCA registration means they follow UK regulatory procedures — including the right to appeal compliance decisions. We use the FCA's complaints framework to escalate unreasonable freezes. CEX.IO is more responsive to legal pressure than offshore exchanges because their FCA registration is commercially critical and they can't afford regulatory complaints.
Source of Funds Request on CEX.IO — our strategy: We prepare a structured Source of Funds package that traces the origin of your funds through every layer: from fiat acquisition to crypto purchase to transfer to the platform. Each step is documented with primary evidence and a cover letter explaining the compliance context.
The submission that matters: Instead of submitting through CEX.IO's standard support channels (where you'll get automated responses or generic template replies), we prepare a professional legal submission — a structured compliance package with a cover letter from a Swiss law firm citing UK Financial Conduct Authority (FCA) obligations and UK Money Laundering, Terrorist Financing and Transfer of Funds Regulations 2017. CEX.IO's compliance team processes legal submissions differently from regular user tickets — they're assigned to senior compliance officers, not support agents, and they bypass the automated response loop that delays most cases by weeks.
When standard compliance isn't enough: Some situations fall outside the normal compliance flow — inherited crypto holdings, accounts registered under another person's name, unprovable source of funds through conventional documentation, or cross-jurisdictional complications where your residence, the exchange's jurisdiction, and the fiat banking path all differ. If that sounds like your case, our complex cases practice handles scenarios that other firms decline.
Further reading: our guide on how to prove source of funds for crypto transactions covers the documentation and legal strategy in more depth.
We trace the origin of your funds through every layer: fiat acquisition → crypto purchase → transfer to {p_name}. {p_name}'s compliance team needs a clear chain — we build it with primary evidence at each step.
We prepare a structured Source of Funds package: bank statements showing fiat origin, exchange purchase records, on-chain transaction history, and a narrative flowchart. Each layer is documented with timestamps and transaction hashes.
We submit the package through {p_name}'s compliance team — not the standard support queue. Our cover letter references {aml_law} and explains the legitimate origin of every transaction in question.
{p_name} accepts the Source of Funds documentation and releases the hold. We confirm your withdrawal and trading functions are fully restored and advise on record-keeping for future {p_name} transactions.
FCA registration means CEX.IO follows UK MLR 2017 procedures, but it doesn't prevent them from freezing accounts they deem high-risk. What it does mean is that they must follow due process: provide reasons for the freeze, allow you to respond, and make a timely decision. If CEX.IO freezes your account without explanation or drags the review out for months, they're violating FCA expectations — and we can escalate to the FCA complaints system.
CEX.IO is FCA-registered; Binance's UK entity (Binance Markets Limited) has had a more complex regulatory journey. CEX.IO is fully compliant with UK MLR 2017 and has a dedicated UK compliance team. This means freezes are more predictable (they follow UK regulatory procedures) but also more stubborn — CEX.IO's compliance team won't unfreeze an account without proper documentation because they face FCA scrutiny.
Acceptable documentation depends on how you acquired your crypto. For earnings: payslips, employment contracts, tax returns. For trading profits: exchange statements showing purchase history. For business income: company registration, audited financials, invoices. For inheritance: death certificate, will, estate distribution documents. For mining: hardware receipts, mining pool records, electricity bills. The compliance team looks for a clear, documented chain from fiat origin to the current crypto balance.
DeFi yields, staking rewards, and liquidity pool returns are legitimate sources of funds — but they're harder to document than exchange purchases. We prepare on-chain evidence: transaction hashes, smart contract interactions, staking pool records, and yield farming positions. The key is showing that your DeFi activity was conducted with funds that themselves have a clear origin.
Yes. Under AML regulations applicable to the platform's jurisdiction, platforms are legally obligated to obtain Source of Funds for high-risk or high-value transactions. Failure to provide adequate documentation gives the platform the right — and in many cases the legal obligation — to close your account and potentially report you to financial authorities.
Tell us what source-of-funds documentation Cex requested and your situation. We respond within 6 hours.