Proof of Reserves
Proof of reserves is published evidence that an issuer or exchange holds the assets it says it holds — typically a third-party verification report on holdings as at a single date, sometimes paired with a cryptographic exercise letting customers check that their own balance was counted. It is not an audit.
Also called: attestation · reserve attestation
Two different exercises travel under the name proof of reserves. The first is a third-party verification report on assets: a firm is engaged to check that stated holdings existed at a stated moment and publishes a report on that limited scope. The second is a cryptographic exercise, usually a Merkle tree, that lets each customer verify their own balance was included in a published total of what the business owes.
Together they are stronger than either alone, and neither is what the name suggests. An assets report says nothing about what the business owes to parties outside the snapshot, about assets pledged as collateral, or about whether the holdings were borrowed for the occasion. The PCAOB, which oversees audits of US public companies, put it more bluntly in a 2023 investor advisory: these engagements are not audits, they sit outside its oversight, and the reports do not provide meaningful assurance to investors or the public. A Merkle exercise proves inclusion in a total; it cannot show that liabilities left out of the tree do not exist. A published wallet address proves control of an address at a moment, not that the balance is unencumbered.
What is worth reading is the engagement itself: what scope the firm accepted, under what standard if any, who signed it, as at what date, and how often it repeats. For a stablecoin issuer, the redemption terms matter at least as much as the reserve figure.
In practice
A proof-of-reserve report is not an audit, and it is not necessarily performed under any established attestation standard. The PCAOB, the US audit regulator, warned in March 2023 that these engagements are not audits and the resulting reports give no meaningful assurance to investors or the public: they verify an asset type at a particular moment, and their procedures likely do not address the firm’s liabilities or the rights and obligations of the people whose balances are being counted. A report of that kind cannot by itself show that an issuer or an exchange is solvent.
Example
A snapshot taken at midnight on the last day of the month shows holdings matching customer balances. That figure does not reveal whether the assets were borrowed two days earlier and returned two days later, whether they are pledged as collateral somewhere else, or what the firm owes to lenders and counterparties who are not its customers.
Commonly confused with
| Term | How it differs |
|---|---|
| Financial audit | An audit gives an opinion on a complete set of financial statements, liabilities included; a proof of reserves reports on assets only, and usually only as at one date. |
| Safeguarding | Safeguarding is a legal obligation about how customer money must be held and who may touch it; proof of reserves is a voluntary disclosure about what is held, with no obligation behind it. |
See also
- StablecoinA stablecoin is a crypto-asset designed to hold a steady value against a reference, almost always a fiat currency such as the US dollar. How that steadiness is supported differs sharply from one issuer to the next, and so does what a holder can actually redeem.
- USDCUSDC is a US dollar stablecoin issued by Circle. The issuer states that it is fully reserved, redeemable one for one by approved account holders, and reported against attestations published by an accounting firm. Those terms are the issuer’s, and the issuer can change them.
- Tether (USDT)USDT, or Tether, is the largest US dollar stablecoin by trading volume and the one most often used in peer-to-peer and emerging-market corridors. It is issued by Tether and is a claim on that issuer, not on a bank or a central bank.
- SafeguardingSafeguarding is the statutory requirement that an authorized payment or e-money firm keep customer funds apart from its own money, by a method the rules prescribe, so the funds are identifiable and returnable to customers if the firm fails. It is a licensing condition, not best practice.
Go deeper
Regulatory information checked: 22/Sep/2026