A reserve attestation is a report by an independent accounting firm confirming that a stablecoin issuer holds enough assets to back all tokens in circulation at a point in time. Circle publishes monthly USDC attestations through Deloitte. It is not a full audit (which examines internal controls over a period), but a snapshot verification that reserves exist at report date.
What Is a Stablecoin Reserve Attestation?
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The short version
An attestation is a spot check. An accountant walks into the vault on a specific day, counts the money, compares it to how many tokens are out there, and says "yes, the money was here on this date." It does not tell you if the money was there yesterday, or if it will be there tomorrow. A full audit would cover those gaps, but most stablecoin issuers provide attestations rather than audits.
How It Works
Process: (1) The stablecoin issuer provides the accounting firm access to bank statements, Treasury holdings, and other reserve documentation on the attestation date. (2) The firm verifies the total assets match or exceed the total token supply (queried from on-chain data). (3) The firm issues a report (typically AICPA AT-C 205 standard in the US) stating whether reserves met obligations at that point in time. USDC: monthly attestations by Deloitte (publicly available on Circle's website). USDT: quarterly assurance opinions by BDO (less frequent, historically more controversial). What an attestation does NOT cover: whether reserves were present every day between reports, the quality/liquidity of reserve assets, internal control procedures, or whether the issuer moved assets out and back between attestation dates (window dressing).
Reading a USDC attestation report
Circle's June 2024 attestation states: "As of June 28, 2024, the fair value of assets held in segregated accounts was $33.1 billion. USDC tokens in circulation on the same date: 33.0 billion." Deloitte confirms: reserves ($33.1B) exceed liabilities ($33.0B) by $100M. Reserve composition: $28.2B in short-term US Treasury bills, $4.9B in cash at regulated banking partners. What this tells you: on that specific day, USDC was fully backed. What it does not tell you: what happened on June 15 or July 5, or how quickly those Treasury bills could be liquidated in a crisis.
What People Get Wrong
An attestation and an audit are the same thing
An attestation is a point-in-time snapshot. An audit examines processes, controls, and activities over a period (typically a full year). Attestations are weaker assurance than audits. No major stablecoin issuer currently publishes full annual financial audits of their reserves specifically, though some are publicly traded companies with audited financials overall (Circle filed for IPO).
Monthly attestations mean the reserves are safe between reports
You are trusting that the issuer does not temporarily move assets between attestation dates. This trust gap is smaller for well-regulated issuers operating under regulatory oversight (where moving reserves would violate regulations), but it is not zero.
If reserves are attested, the stablecoin cannot fail
An attestation confirms assets exist, not that they are instantly liquid or that the issuer is operationally sound in all ways. The SVB incident showed that even fully-backed reserves can be temporarily inaccessible if the banking partner fails.
Keep Reading
Sources & Further Reading
- Circle USDC Attestations
Monthly attestation PDFs from Deloitte on USDC reserves
Questions People Also Ask
- Where can I read USDC attestation reports?
- Circle publishes them monthly at circle.com/en/transparency. Each report is a PDF signed by Deloitte, stating the attestation date, reserve total, token supply, and reserve composition. They are free to access and worth reading if you hold significant USDC.
- Does Tether (USDT) publish the same type of report?
- Tether publishes quarterly assurance opinions by BDO Italia. They are less frequent (quarterly vs. monthly) and have historically been less detailed about reserve composition. Tether's transparency has improved since 2022 but still draws more scrutiny than USDC's reporting.
- Should the lack of a full audit concern me?
- It is a fair concern. A full audit provides stronger assurance. However, monthly attestations combined with regulatory oversight (Circle is regulated as a money transmitter and licensed in multiple states) provide meaningful transparency. The situation is improving as regulations like MiCA require more rigorous reserve disclosure.