An unbroken documentary trail from where the money was earned or realised to the account that funded the enterprise: sale agreements, statements, tax records and transfer confirmations.
Every hop in the chain needs a document
Hypothetical example: The proof is not a statement of net worth. It is a narrative supported at each step: how the funds were lawfully generated, what happened to them between then and now, and how they reached the enterprise. A Selwyn couple funding a purchase from the sale of an existing business would show the sale agreement, the closing statement, the deposit into their account, any intermediate transfers, and the payment to escrow.
Where funds came from a mortgage or a loan, the security matters — borrowing secured against the applicant's own assets can qualify, while debt secured by the assets of the enterprise itself does not count as the investor's own committed capital. Gaps in the chain, particularly transfers through accounts held by relatives or corporations, are where files stall, and they are far easier to document as they happen than to reconstruct later.