Casino Source of Funds Checks: The Documents You Need

This means so-called "source of funds" checks are not about proving how much money a customer has overall, but about tracing the specific pot of cash they are using for gambling. So the documents casinos ask for related to that funding source.

What the Check Is

Source-of-funds checks are a key way UK casinos patrol gambling crime. Under UK regulations, these operators must use source-of-funds and source of wealth checks to trace the origins of the money that customers gamble with. Which is aimed at preventing dirty money from being laundered via gambling venues.

The operator has to specify to regulators how customers have “gained, generated, inherited, won, borrowed or bequeathed the money / property used in gambling”. And to prove customers funded their accounts via legitimate channels.

On the regulator's website, it said: "Evidence of a customer's source of funds will depend on what the source actually is. The evidence provided should be comprehensive enough to build up a picture of the source of the total funds."

In other words, the Gambling Commission UK says evidence should connect a total pot of funds used for gambling to a single known source, such as savings, salary, sale proceeds, investments, inheritance or crypto.

What Documents Casinos Ask For

A third-party guide summarising casino "source of funds" checks in general named documents that casinos typically ask for. A list including recent payslips, salary slips, tax returns, investment portfolio statements P60s, bank statements, sale contracts, sale contract receipts, building society passbooks and inheritance documents. It also included gift documentation, screenshots of funds transfer history and cryptocurrency exchange transactions.

But the regulator's guidance page says the evidence is context-dependent.

"That evidence can sometimes be complex - it could be anything from a set of payslips, to a sale contract, to cryptocurrency transaction records. There is not one single form of evidence that will be appropriate for all customers."

In the same guidance, the Gambling Commission says asking a customer to provide “significant” or “extensive” documentation is the result of a risk assessment. It "will be related to the nature of the customer's 'source of funds'" and "the purpose of these checks is not to assess the total customer wealth".

But the commission does not say how much information customers must provide to “satisfy” a check linked to salary, savings, sale of property, inheritance, gifts, or crypto. Nor does it spell out fully the full distinction between customer due diligence, enhanced due diligence, and source of funds versus source of wealth in gambling AML guidance.

If the casino seizes on this vagueness

What the Regulator Says

The Gambling Commission UK's guidance page on source of funds evidence was published on its website on 26 August 2026. The page gave broad examples of the documents it accepts as "adequate" evidence of source of funds, depending on the stated source. But it does not break this down into specific document types.

This is the Commission's key official word on the matter: "Evidence should relate to the total funds used in gambling at that point in time, so an operator assessing the source of funds for a customer depositing £2,000 will need to see evidence of sources to cover that total amount."

But the Commission imposes no stringent requirement that operators get the documents themselves. The page states simply that operators may accept copies or notifications of those documents, as long as they have not expired nor been altered and as long as the original files are retrievable.

The commission does not lay out a timeline for when casinos must perform checks, nor for how long customers must provide documents.

This appears to be the Gambling Commission UK's primary-source wording on the bones of source-of-funds checks for gambling operators. And it is not decisively grounded in anti-money-laundering regulation or statutory decisions on fund-tracing.

In its funding page, the commission UK repeats that its work is funded by fees paid directly by the gambling industry, while its regulatory work is funded by application and license fees authorised by the Department for Culture, Media & Sport, approved by Parliament and paid by gambling firms Its annual report and accounts stated that this applies to its National Lottery activities as well.

But in a 2026 trust statement, the commission also mentioned receiving a share of financial penalties paid to the Consolidated Fund. It also said it receives a share of the economic crime levy.

What This Does Not Prove

If a casino asks for documents, it is a step in tracing the particular pot of money, not the operator's overall fortune.

Source-of-fund checks serve to trace only the specific piece of cash that a player is giving for gambling. And "source-of-funds checks are not about assessing customer wealth."

So there's nothing to help establish the true size of a gambler’s assets, home, business, investments or total earnings.

That may explain the casinos' authority to freeze withdrawals during a source-of-fund check. It leads to a common attack that casinos are "laundering players' wages and desire to contact jackpot winners."

Practical Response

So what should you send? The regulator itself provides guidance: "Example could be a set of payslips from an employer to evidence earnings are the true source of funds. Alternatively, the customer could provide a letter from their lawyer/ accountant evidencing the source."

The third-party guide includes generating payslips, bank statements, screenshots of the transaction history, statements of inactive accounts, royalty payments, partnership accounts, gift documentation, building society passbooks/building society book.

The guide warns against giving personal addresses, lottery winnings, rent, pension numbers, utility bills, documents with missing pages, or screenshots from the casinos themselves.

Notice the caveat here: this is a third-party description of the relevant documents, not an official, definitive statement from the Commission.

If you receive a request, remember the regulator's advice that these checks are not a way to assess total wealth, but to check just the source of gambling funds.

When asked, check with a qualified solicitor in your country. If a document is printed from your bank online, then sign the printed copy and hand sign it...