"Source of funds" and "source of wealth" sound like the same thing said two ways. They are not. The distinction is one of the most useful — and most frequently muddled — ideas in due diligence, and getting it right is central to enhanced due diligence.
The two definitions
Source of funds (SOF) is the origin of the specific money involved in a particular transaction or relationship. Where did this money come from? Examples: the proceeds of a named property sale, a salary payment from a named employer, a dividend from a specific company, a loan from a specific lender.
Source of wealth (SOW) is the origin of a person's overall wealth — the bigger picture of how they came to have money at all. How did this person become wealthy in the first place? Examples: a career as a senior executive, the sale of a business they founded, inheritance, long-term investment returns.
A useful way to hold the difference: source of wealth explains the pile; source of funds explains the slice of it being used right now.
Why both matter
The Money Laundering Regulations 2017 require firms applying enhanced due diligence — for example to a politically exposed person, or in other higher-risk situations — to establish the source of funds and source of wealth involved. The FCA's PEP guidance is explicit that, for PEPs, understanding source of wealth and source of funds is part of the enhanced measures.
Why both? Because each answers a question the other cannot:
- SOW tests plausibility. If someone's known career and assets could never have generated the wealth they hold, that is a red flag in itself — a classic signature of corruption or laundering.
- SOF tests this transaction. Even someone with entirely legitimate overall wealth can route a specific, dirty payment through a clean account.
The question that ties them together
The single most important test in any SOF/SOW review is this:
Does the source of funds make sense given the source of wealth?
A retired civil servant on a modest pension wiring a seven-figure sum is not, by that fact alone, a criminal — but the mismatch between the slice (a large transfer) and the pile (a modest pension) demands explanation. Conversely, a successful entrepreneur reinvesting the documented proceeds of a business sale is exactly what you would expect. Due diligence is, at heart, the discipline of noticing when the story does not add up.
Evidence, not assertion
For both SOF and SOW, the standard is corroborated evidence proportionate to the risk — not the customer's say-so. Depending on the case, that might mean:
- for SOW: documentary evidence of the wealth-generating events (sale agreements, audited accounts, employment records, probate documents);
- for SOF: evidence tracing the specific funds (bank statements, completion statements, dividend vouchers).
The higher the risk, the more independent and robust the evidence should be.
Where Probitas fits
A great deal of source-of-wealth plausibility testing starts with the public record: what companies does this person own or control, what do those companies actually do, what do their filed accounts show, and does any of it square with the wealth on display? Probitas reads exactly that record — ownership chains, PSC data, filed financials, adverse media — and presents it with citations, giving you an evidenced starting point for the SOW question. Confirming source of funds for a specific transaction, and reaching a conclusion, remains part of your own due-diligence process.
Sources
This guide is written from primary sources. Each is linked below; claims in the text link to the specific reference they rely on.