Explaining Source of Funds and Source of Wealth: Why Banks Ask, How Far They Go and How to Prepare

Source of funds (SoF) is where the specific money used to open an account or for a particular transaction comes from, for example this month's salary, the proceeds of a property sale or a matured time deposit. Source of wealth (SoW) is how a customer's overall wealth was built up, for example years of employment income, running a business or an inheritance. Hong Kong banks ask about source of funds at almost every account opening, but source of wealth needs to be established only in higher-risk situations. That risk-based position is set out clearly in the AML FAQ issued by the Hong Kong Association of Banks with the HKMA.

Applies to: Hong Kong (a Singapore comparison follows at the end). This page covers source-of-funds explanations for retail and corporate account opening only. In-depth source-of-wealth checks at private banks are covered in privatebank.hk private bank on-boarding and KYC, and accounts and fund flows for insurance policies in vul.hk account opening routes. This page does not provide document templates or write explanations for you.

Two concepts: how they differ and how they connect

The two support each other: source of wealth explains "how much money you might plausibly have", and source of funds shows "whether this particular money fits". Appendix 1 of the Hong Kong Association of Banks AML FAQ of 2024-12-30 lists "failing to distinguish between a customer's source of wealth and source of funds" as one of banks' poor practices, so banks ask about them separately, and you should prepare for them separately too.

The regulatory position: risk-based, with no requirement for everyone to prove source of wealth

Schedule 2 of Cap. 615 requires banks to understand the purpose and intended nature of the business relationship. For higher-risk situations such as politically exposed persons, the Ordinance and HKMA guideline require banks to take reasonable measures to establish source of wealth and source of funds.

The FAQ issued by the Hong Kong Association of Banks (prepared with HKMA participation) sets the scale out clearly:

1. Not every customer. Q50: collecting source-of-wealth information "is generally applicable to higher risk situations", and banks are "not required to establish the source of wealth of every customer".
2. Occupation and similar information is enough for ordinary customers. For most customers who are not high risk, information such as an individual's occupation or a company's nature of business should be enough for the bank to understand the customer and monitor whether transactions are in line with expectations.
3. No need to go back decades. Even where source of wealth must be established, banks need not apply the same procedure to all such customers, or ask for evidence going back decades when the risk does not justify it.
4. Corroboration and net-worth verification are not always needed. Q51: banks should decide the depth of measures on a risk basis; it is not necessary in every case to obtain evidence corroborating the information the customer provides or to verify an individual's net worth. Where appropriate, key points can be corroborated from reliable, independent sources (such as public property, land or company registers).

So being asked "where does the money come from" is routine. Being asked to prove source of wealth usually means the case has been assessed as higher risk, or that the amount of money needs more explanation relative to your background.

Information sources banks accept and common evidence

Appendix 1 of the Hong Kong Association of Banks FAQ lists four types of source for source-of-wealth information. The table below maps them to document types commonly seen in personal account opening (whether a document is accepted is for the bank to decide):

For source of funds, the most direct evidence is a document showing the flow of money, such as a statement from the remitting bank showing that the funds came from accumulated salary, a property sale or an investment redemption. Three principles help when preparing:

• Traceable: each larger amount can be linked to a source event;
• Verifiable: documents are issued by a third party, with clear dates, amounts and names;
• Proportionate: the amount of money broadly fits your occupation, age and business circumstances; where there is a large gap, add background proactively.

Why banks follow up: reading back from the "poor practices" list

Appendix 1 of the Hong Kong Association of Banks FAQ lists banks' poor practices on source of wealth, which helps explain why banks ask follow-up questions:

Appendix 1's good practices also include reassessing when business activity departs from the customer's source of wealth. This means that if the way you use the account changes markedly after opening (for example, large sums suddenly moving in and out), the bank may come back with questions. How to respond to a request for documents or explanations is covered in Rejections, document requests and account closure.

How the investment account declaration relates to a source-of-funds explanation

From 2026-05-22, Chinese Mainland investors opening an investment account, or adding the investment function of an integrated account, must sign a written declaration, the first point of which confirms that all funds supporting the investment activities and related settlement "come from lawful sources outside the Mainland" (HKMA circular, Annex 1, Measure 3). Its relationship to an ordinary source-of-funds explanation is as follows:

The declaration does not replace a source-of-funds explanation; the bank must still carry out normal due diligence and transaction monitoring. Nor is the declaration a formality you simply sign. The prohibitions in Mainland foreign-exchange rules are covered in Mainland residents opening accounts in Hong Kong, and the full declaration in Investment account changes.

Consistency: one person, four places, one story

Banks look at information from different stages together, and inconsistencies often prompt more follow-up than missing information does.

On tax, under section 80(2E) of the Inland Revenue Ordinance, knowingly or recklessly making a statement in a self-certification that is misleading, false or incorrect in a material particular may lead to prosecution (IRD penalty policy); how to complete the CRS form is covered in CRS and tax residence self-certification. The documents themselves must also be genuine: the SFC circular of 2026-05-22 notes that the consequences of submitting forged documents include termination of the account, a report to law enforcement agencies and possible criminal prosecution.

How Singapore compares

Singapore's position is also risk-based. MAS Notice 626 requires banks to understand the purpose and intended nature of the business relationship, and for higher-risk customers such as politically exposed persons, to establish source of wealth and source of funds by appropriate and reasonable means (paragraph 8.3, current version revised 2025-06-30). On enforcement, MAS took regulatory action against 9 financial institutions on 2025-07-04, with penalties totalling S$27.45 million, for shortcomings including failing to follow up adequately on concerns about customers' source of wealth.

What the two places have in common is that ordinary customers mainly explain their occupation and account purpose, and source of wealth is examined in depth only in higher-risk situations; the difference is that Hong Kong also has a written declaration for Chinese Mainland investors' investment accounts. The Singapore approach to KYC and source of funds is covered in bankaccount.com.sg source of funds and source of wealth (in English).

If you would like help organising a source-of-funds explanation for your own situation, you can register your enquiry through this site's contact details. This page is not legal or tax advice; whether the bank accepts an explanation is decided by its own risk assessment.