Source of funds vs source of wealth: what evidence is actually enough

The client has provided a bank statement, confirmed their account balance and is ready to proceed with the transaction. Yet the central AML question remains unanswered: how did they earn or obtain this money? Transfers between their own accounts show the movement of funds but do not explain their original source. Even substantial wealth does not resolve questions about a particular payment if the documents fail to connect it to the stated income source. Assessing whether the evidence is sufficient requires distinguishing between source of funds and source of wealth, then checking whether the documented explanation is consistent with the transaction and the client’s profile. In this article, we examine the differences between these checks, the documents supporting various income sources and the criteria that help reach a well-founded decision.

Source of funds vs source of wealth: what is the difference?

Source of funds (SoF) identifies where the money used for a specific transaction or business relationship came from. Source of wealth (SoW) explains how the client accumulated their overall wealth. These checks are related but serve different purposes: confirming the origin of one payment does not establish the full history of a client’s wealth, while a known source of wealth does not automatically explain every new transaction.

For example, a client transfers €250,000 for an investment and states that they built their wealth through a construction business. Information about company ownership and income received may support their source of wealth explanation. However, establishing the source of funds requires identifying where this particular €250,000 came from: dividends, an asset sale, a loan or another source.

The distinction can be framed through the questions each check should answer:

1. Source of funds. What event or activity generated the funds for the transaction, and how did the client receive them?
2. Source of wealth. What principal sources contributed to the client’s wealth, and how consistent is its size with the documented history of their income and assets?

The statement “the money came from another bank” therefore describes the transfer route, but not necessarily the origin of the funds. Similarly, describing someone as an “entrepreneur” does not, by itself, explain the scale of their wealth. In both cases, the stated source must be connected to verifiable information.

The evidence may nevertheless overlap. Selling a company can explain both a substantial portion of the client’s wealth and the funds used for a subsequent investment. AUSTRAC notes that documents supporting SoW may also substantiate SoF when the sources coincide. The key is to understand what conclusion each document supports, rather than mechanically collecting two separate sets.

When are source of funds and source of wealth checks needed?

The depth of the checks depends on applicable AML requirements, the nature of the service and the risk associated with the particular relationship. Not every client needs to substantiate their entire wealth history. However, a low initial risk rating does not rule out additional enquiries if subsequent transactions differ from those described.

Certain circumstances explicitly require source of funds and source of wealth checks. For example, UK HMRC guidance specifies the need for SoF and SoW checks when establishing a business relationship with a politically exposed person (PEP). It also explains that ongoing monitoring includes examining the source of funds where necessary to assess whether transactions are consistent with the client’s known profile. These requirements should be applied within the context of the relevant jurisdiction and regulated sector.

Circumstances that may warrant further scrutiny include:

1. An amount inconsistent with the client’s profile. The transaction size differs significantly from their known income, turnover or expected activity.
2. Third-party involvement. Funds come from someone whose connection to the client and role in the transaction are unexplained.
3. A change in payment patterns. Instead of the stated business income, the client begins receiving substantial gifts or loans.
4. A complex flow of funds. Multiple intermediaries or accounts make it difficult to establish the original source.
5. Conflicting information. The client’s explanations contradict documents or reliable information from other sources.

Each factor requires assessment but does not, by itself, prove that the money is illicit. For example, a payment from a relative may have a clear rationale that needs to be substantiated proportionately to the risk.

A practical approach starts by defining the specific question: the origin of an individual payment, the client’s ability to accumulate their stated wealth, or both. Then determine the necessary depth of verification and document the rationale for that decision. If new information changes the risk assessment, the scope of the checks should be reassessed.

What documents support different sources of funds and wealth?

Documents should be selected according to the stated source of money and the specific question being examined. The aim is to establish the basis on which the funds were obtained, their receipt by the client and their connection to the transaction under review. Evidence may include employer records, asset sale documents, inheritance records and other supporting information. AUSTRAC provides these examples, but their sufficiency depends on the circumstances: no single set of documents suits every client.

Employment income, dividends and business sales

Payslips, employer records, tax documents and statements showing regular incoming payments may support savings accumulated from employment income. If a client attributes a substantial sum to years of saving, evidence of their latest salary alone does not explain that accumulation. The stated savings should be assessed against the duration of employment and income earned.

Dividends may be substantiated through evidence of share ownership, a resolution approving the distribution of profits and confirmation of payment. Financial statements help assess the economic basis for the distribution. However, company profits do not equal a shareholder’s personal income: the amount actually received by the client must be established.

For a business sale, review ownership of the shares sold, the agreement, completion documents and evidence of payment. The contractual price may include deferred or contingent payments. It should therefore not automatically be treated as an amount already available to the seller.

Inheritance, gifts and loans

Inheritance may be supported by documents establishing entitlement, records from the executor or estate administrator, and confirmation of asset distributions. These should establish what the client received and when. If inherited property was subsequently sold, the inheritance must be linked to the sale and receipt of the proceeds.

Gifts and loans require an understanding of the relationship between the parties. An agreement or donor declaration explains the basis for the transfer, while payment records confirm the movement of funds. Depending on the risk, the donor’s or lender’s source of funds may also need to be checked. Receiving a loan does not, in itself, demonstrate that the client accumulated equivalent wealth: the funds come with a repayment obligation.

Investments and cryptoassets

Brokerage statements, asset purchase and sale histories, and records of distributions and withdrawals can support investment income. Distinguish between the portfolio’s current value, realised gains and the amount actually received by the client.

For cryptoassets, a practical evidence set may include platform transaction histories, proof of the initial acquisition, wallet information and records of conversion to and withdrawal in fiat currency. A blockchain record shows an asset’s movement but does not, by itself, establish the owner’s identity or the economic basis for receiving it. Transaction data must therefore be assessed alongside evidence linking the wallet to the client and their explanation of the assets’ origin.

How much evidence is enough to reach a defensible conclusion?

The sufficiency of evidence depends on whether it supports a reasonable explanation of the source of funds or wealth, taking account of applicable requirements and the identified risk. A fixed number of documents cannot replace this assessment. Even several authentic records may leave the central question unanswered if they relate to a different period, asset or recipient.

When analysing the information collected, consider five criteria:

1. Source reliability. Who issued the document, can its origin be verified, and how independent is the source from the client?
2. Connection to the client. Does the information confirm that the income or asset belonged to this particular client?
3. Consistency of amounts and dates. Do the actual receipts correspond to the stated event, allowing for taxes, fees and instalments?
4. Continuity of the funds’ movement. Is it clear how the money moved from its source to the transaction under review, and are significant intermediate transfers explained?
5. Consistency with the financial profile. Does the explanation align with the client’s known activities, accumulation period and income levels?

For example, an agreement provides for the sale of a shareholding for €600,000, but the client owned only half of the shares being sold. Evidence of the total transaction price does not explain why they received the entire amount. An additional bank statement will not resolve the issue either unless it establishes the basis for allocating the proceeds.

The assessment conclusion should be documented separately from the supporting records. It should identify the stated source, the evidence reviewed, any discrepancies and the explanations accepted as resolving them. If certain information cannot be obtained, record the alternatives used and any remaining limitations.

The criterion for completion is whether the assessment can be explained and its reasoning reconstructed during an internal review or regulatory inspection. A material contradiction cannot be considered resolved simply because the client has provided a large volume of documents. If it remains unresolved, further review under the established procedure is required.

What to do when documents are missing or inconsistent

Missing documents and inconsistent information require different approaches. A client may no longer have evidence of an old transaction, even though its circumstances can be verified through other sources. However, if the stated sale is inconsistent with information about the asset’s owner or the actual payer, the reason for the discrepancy must be established.

Start by defining the specific gap. Instead of repeating a request to “prove the source of the money”, explain exactly what needs to be established: ownership of the property sold, receipt of an inheritance or the basis for a third-party payment. Clarify whether the original document exists and whether a duplicate can be obtained.

Alternatives may include archived bank records, extracts from official registers, documents from an executor or confirmation from a professional involved in the transaction. Their value depends on their content and verifiability. For example, an adviser’s letter that merely repeats the client’s statements does not provide the same level of support as information based on a review of primary documents.

If material questions remain, escalate the case internally. The responsible specialist should receive the client’s explanation, the evidence collected and a precise description of the unresolved issue. The next decision must follow applicable rules and internal approval procedures: continue the checks, restrict the transaction or decline to establish or continue the relationship where the circumstances and the law require it.

An inability to substantiate the source should not automatically be equated with proven money laundering. If suspicions arise, separately assess the obligation to submit a report to the competent authority and any restrictions on informing the client.

Finally, requests should remain targeted. If another document will not help resolve a specific gap, obtaining it merely adds to the file. The decision to complete the checks must rest on the substance of the evidence and mandatory requirements, rather than an internal deadline or the client’s commercial value.

How Structum supports source of funds and wealth checks

Verifying the source of funds requires a clear methodology, skilled analysis and documented conclusions. Structum helps companies integrate SoF and SoW checks into their AML processes: define the grounds for information requests, assign responsibilities and establish procedures for handling complex cases. The approach takes account of business activities, client profiles and applicable requirements.

The Structum team helps to:

• Assess existing source of funds and source of wealth procedures;
• Identify circumstances requiring additional information or more detailed analysis;
• Develop guidance on supporting documents for different income sources;
• Prepare clear client requests aimed at resolving specific gaps;
• Organise client file reviews and the documentation of conclusions;
• Establish internal escalation procedures and allocate decision-making authority;
• Train staff to assess evidence and identify material inconsistencies;
• Recruit AML specialists experienced in assessing complex sources of funds.

Particular attention is given to connecting procedures with the team’s day-to-day work. Staff should understand why each document is requested, which information needs verification and when a case requires further review. Management needs visibility of unresolved issues and the resources required to address them.

Contact Structum to assess your current approach to SoF and SoW or develop procedures for a new business area. We will help establish a consistent review process and clear reasoning for decisions that can support internal controls and engagement with regulators.