What they are actually asking
Compliance needs two things: your source of funds (where the money in this particular transaction came from) and often your source of wealth (how you built the capital in the first place). Your answer has to connect the origin of the money to the balance on the platform through an unbroken chronology — that is the main test of a good file.
What to evidence it with, by type of income
- Employment: income statements, bank statements showing the credits, your employment contract.
- Business: company statements, tax returns, dividend documentation.
- Trading: trade history from the platforms, withdrawal reports, tax returns showing the declared income.
- Early crypto investment: the hardest case — rebuild the chain: the first purchase (receipt, bank statement, screenshot), movement between wallets, current balance. Here your on-chain history works in your favour.
- Sale of property, inheritance, gift: contracts, certificates, statements showing the receipt.
Rules for the file
- One package, not a correspondence: a covering letter plus numbered exhibits.
- An unbroken chronology: every significant transfer accounted for.
- Do not attach anything extra: documents outside the scope of the request generate new questions.
- Do not understate or "round" the figures: mismatched amounts are the single biggest trigger for repeat requests.
Our builder assembles the framework of the letter with wording matched to your type of income — the button is below.
What the reviewer is actually checking
A source-of-funds (SOF) request asks where this specific money came from; a source-of-wealth (SOW) request asks how your overall assets were built. Exchanges send them as part of enhanced due diligence (EDD) — the deeper tier of the customer due diligence (CDD) that AML law requires, anchored internationally in FATF Recommendation 10 and, in the EU, in the anti-money-laundering framework (AMLD5 and the incoming AMLR). The file is read by a compliance officer against a known list of red flags: structuring (many deposits just under reporting thresholds), rapid in-and-out movements, round-tripping between your own wallets without economic purpose, and amounts that do not match the declared income.
Two technical points strengthen almost any file. First, prove wallet ownership properly — a message signed from the wallet’s key is stronger evidence than a screenshot. Second, document beneficial ownership plainly if any funds passed through a company or a relative: an unexplained third party in the chain is one of the fastest routes to escalation. Certified translations and notarised copies are rarely demanded at the first round, but having them ready shortens the second.
The file that gets a review closed in weeks rather than months isn’t the one with the most documents — it’s the one with no gaps in the timeline. We’ve seen otherwise-clean early-crypto files get bounced back three times because a single six-month period between a 2019 purchase and a 2021 wallet transfer had no supporting evidence at all. If you can’t fully document a gap, say so explicitly rather than leaving it silent; compliance teams read silence as concealment.
Mark Eichorn · Managing Partner
Frequently asked questions
What should I put for source of funds?
The category of origin (employment, business, investment, sale of property) plus the short facts: period, amounts, supporting documents. Generalities without documents do not work.
Is it lawful to demand proof of source of funds?
Yes: AML regulation obliges platforms to check where funds come from. Refusing to answer almost always ends in the account being closed.
Why does my bank also ask for source of funds on a withdrawal from an exchange?
The bank has its own AML obligations: an incoming payment from a crypto platform is a standard trigger. Prepare the same file in advance.
Source-of-funds letter builder
Build the framework of your compliance reply: structure, wording and the list of attachments — tailored to your income type.