A Modified Gresham's Law of Stablecoins

Key Takeaways

• USDT $189B, USDC $77B; gap widening
• Illicit crypto inflows hit $154B in 2025
• Tether froze $3.3B vs Circle $109M (2023‑25)
• Compliance‑by‑design could align privacy and AML

Pulse Analysis

The rise of stablecoins has introduced a digital analogue to Gresham’s classic observation that inferior money drives out superior money. While both USDT and USDC promise a one‑to‑one U.S. dollar peg, their backing structures differ dramatically. Tether’s reserves are a mix of cash, Treasuries, gold, Bitcoin and unsecured loans, and the firm has never undergone a Big Four audit. Circle, by contrast, relies on a money‑market fund holding only Treasury securities and submits to regular Deloitte audits and New York regulator oversight. This transparency gap, combined with the anonymity afforded by self‑custody wallets, makes USDT the preferred vehicle for illicit actors, a trend reflected in the surge of illicit blockchain receipts to $154 billion in 2025 and USDT’s market‑cap dominance.

Regulatory frameworks such as the Bank Secrecy Act and the 2025 GENIUS Act focus on institutions—exchanges, custodians, and on‑ramps—rather than the tokens themselves. Consequently, once stablecoins move into a self‑hosted wallet, they become bearer‑like instruments that evade direct AML scrutiny. Issuers can blacklist addresses, but data show Tether froze $3.3 billion across more than 7,000 addresses, while Circle froze only $109 million, indicating that blacklisting alone cannot stem illicit flows. The real bottleneck is identification, which only occurs at the points where tokens intersect the regulated financial system.

Policymakers are exploring a middle ground through “compliance‑by‑design” architectures that separate identity verification from transaction execution using zero‑knowledge proofs. While technically promising, the added latency and cost currently hinder mass adoption. A more immediate solution lies in tokenized deposits—bank‑backed digital claims that retain the programmability of stablecoins while embedding identity verification at the ledger level. By extending AML obligations to the instrument itself, tokenized deposits could neutralize the modified Gresham’s Law effect, offering users privacy where appropriate without furnishing a safe haven for criminal finance.