Proof of funds and proof of control: what to ask for, and what to accept
Key takeaways
- Proof of funds evidences existence; proof of control evidences authority to move. A transaction needs both, from both sides.
- For digital assets, the only strong proof of control is a message signed with the private key of the holding address, or a transfer executed on request.
- Screenshots, PDF bank letters with no verification path and third-party attestations naming no bank officer are not evidence and should be treated as absent.
- Whatever is accepted must be defined in the term sheet before the first tranche, because renegotiating evidence standards mid-block is how blocks stall.
Almost every stalled OTC transaction stalls at the same point: one side asks the other to demonstrate that the assets or the money are real and theirs, and what comes back does not do that. The confusion is usually terminological, so it is worth being precise.
Two different claims
Proof of funds answers: do the assets exist, in the stated amount, unencumbered. Proof of control answers: can the party in front of me move them. They are independent. A balance can be real and controlled by someone else; a wallet can be controlled and empty.
A transaction needs both claims evidenced, from both sides. Buyers routinely demand both from sellers and offer neither in return, which is one reason sellers become uncooperative.
What stands up on the asset side
- A signed message. An agreed text signed with the private key of the holding address, verified against that address. This is the strongest evidence available and it costs nothing.
- A transfer on request. A nominal amount moved from the holding address at a moment the other side chooses. Slower, but conclusive.
- A custodian attestation naming the account, the balance and an officer who can be contacted.
What does not stand up: a screenshot of an exchange balance, a block explorer link to an address anyone could have named, or a "wallet screenshot" with a pasted address.
What stands up on the cash side
- A recent bank statement on the institution's own channel, or a bank letter naming an officer with a verification route.
- A read-only view of a balance, granted temporarily.
- A blocked-funds confirmation issued bank to bank, where the structure warrants it.
What does not stand up: an unverifiable PDF, a letter with no named officer, or an attestation from a party with no stated relationship to the bank.
Set the standard before the first tranche
The practical failure is not that parties refuse to provide evidence — it is that nobody agreed what would count. Write the evidence standard into the term sheet alongside the tranche schedule: what each side will produce, in what form, and by when. Renegotiating it after the first transfer has been promised is how a live block turns into a dead thread.
Proportionality
Demanding a bank-issued blocked-funds confirmation for a twenty-thousand-dollar first tranche signals inexperience as loudly as offering a screenshot does. Match the evidence to the exposure: a signed message and a nominal test transfer are enough to start almost any block, and the standard tightens as tranche size ramps.
Questions this answers
- What counts as acceptable proof of funds in an OTC transaction?
- A recent bank statement or a bank-issued letter with a named officer and a verification route; a custodian attestation; or, for stablecoin buyers, an on-chain balance in an address whose control can be demonstrated. Screenshots and unverifiable PDFs are not proof, however official they look.
- How do you prove control of a crypto wallet?
- Sign an agreed message with the private key of the address holding the assets, and let the other side verify the signature against that address. A small transfer executed on request achieves the same thing. A balance alone proves nothing about who can move it.
- Can a seller prove control of coins held on an exchange?
- Generally no. Exchange deposit addresses belong to the exchange and are often pooled, so the account holder cannot sign from them. That is why serious sellers move inventory to self-custody, or to a segregated custodian address, before going to market.
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