USDT vs USDC:
Custody & Reserve Transparency
The two largest stablecoins hold a combined $200B+ in reserves. But who custodies those reserves, how are they verified, and what happens if either issuer fails? This is the custody-focused comparison that most analyses overlook.
USDC has the stronger custody architecture: BlackRock manages the reserve fund, BNY Mellon custodies the assets, and Deloitte provides both monthly attestations and annual audits. USDT has more market share but relies on attestations from a non-Big 4 firm, has no published full audit, and operates from the British Virgin Islands — outside the GENIUS Act's jurisdictional reach.
Full Custody Comparison
| Category | USDC (Circle) | USDT (Tether) |
|---|---|---|
| Issuer | Circle | Tether Holdings |
| Market Cap | ~$56B | ~$145B |
| Launch Year | 2018 | 2014 |
| Reserve Custodian | BNY Mellon, BlackRock | Cantor Fitzgerald |
| Reserve Assets | U.S. Treasuries, cash at regulated banks | U.S. Treasuries, Bitcoin, gold, secured loans |
| Reserve Manager | BlackRock (Circle Reserve Fund) | Tether internal management |
| Attestation | Monthly (Deloitte) | Quarterly (BDO Italia) |
| Full Audit | Annual (Deloitte — Big 4) | None published |
| GENIUS Act Ready | Yes — U.S. domiciled, regulated custodian | Uncertain — BVI domiciled |
| U.S. Domicile | Yes (Boston, MA) | No (British Virgin Islands) |
| Reserve Segregation | Yes — legally segregated trust | Not publicly confirmed |
| Rehypothecation | Prohibited | Not publicly disclosed |
| On-Chain Proof of Reserves | Circle publishes CCTP data | Not available |
| Insurance | FDIC-insured bank deposits for cash portion | Not disclosed |
| Regulatory Status | NY BitLicense, state money transmitter | No U.S. license |
Data based on public disclosures as of February 2026. Market cap figures are approximate. This is not financial or legal advice.
Who Custodies the Reserves?
BlackRock manages the Circle Reserve Fund, a regulated money market fund investing exclusively in short-term U.S. Treasuries and repurchase agreements.
BNY Mellon serves as the primary custodian for the fund's Treasury holdings — the oldest bank in the United States.
Cash reserves are held at FDIC-insured banks including JPMorgan, Customers Bank, and Cross River Bank.
Cantor Fitzgerald holds a significant portion of Tether's Treasury exposure. In 2024, Cantor acquired a ~5% stake in Tether.
Tether also holds Bitcoin (~$7.7B as of Q4 2024), gold, and other investments that are not part of the GENIUS Act's permitted reserve assets.
Reserve details come from quarterly attestations by BDO Italia, not from a Big 4 auditor. No full audit has been published.
Audit vs Attestation: Why It Matters
An attestation is a point-in-time snapshot: an accounting firm confirms that on a specific date, reserves existed. It does not examine the systems, controls, or processes that manage those reserves over time.
A full audit examines financial statements, internal controls, and operational processes over an entire reporting period. It provides much higher assurance that reserves are consistently maintained, not just present on attestation day.
The GENIUS Act requires monthly attestations for all issuers and annual audits for issuers above $50B. Under this framework, both USDC and USDT would need full audits — but only Circle currently has one.
See All Stablecoin Scores
USDC and USDT are just two of the stablecoin issuers and custody providers we score. See the full rankings.