FinWiki
日EN中

Dual-currency arbitrage · the §501 legal hack and regulatory fragility

Confidence: Likely Updated 2026-05-26 Review by 2026-08-08 Sources 5 Machine-translated Original (JA)
#fintech#fx#legal-hack#genius-501#mica#japan-psa
On this page

Wiki route

This entry sits under fintech index. Read it with Japan Financial Regulation — Legal Framework for Tokens, Crypto Assets, and Payments for adjacent context and Three-Layer Structure of Japan's Stablecoin Regulatory Regime (JPYC, USDC, Project Pax) for the broader system boundary.

[!info] TL;DR The legality of dual-currency stablecoin arbitrage rests on a single legal hack: “an atomic swap between 2 independent payment stablecoins is not an FX business.” This gives on-chain FX legal room. But the weak point of the hack is that the moment any of the US / EU / Japan regulators redefines a “dual-currency swap” as an “FX business” → the entire structure becomes void. Notices from the SEC / OCC / FCA / FSA need to be monitored continuously.

Key facts

  • The GENIUS Act §501 does not prohibit cross-currency “via holding ↔ swap” · it prohibits only FX business by the issuer
  • MiCA Title IV already permits multiple issuers of EUR-stablecoins = effectively equivalent to encouraging on-chain EUR FX liquidity
  • The Japan PSA 2023 amendment defines a stablecoin as an “electronic payment instrument” · it does not explicitly classify swaps as FX
  • Euro stablecoins such as SocGen EURCV / Lugh EURL provide pluralization of regulation

Mechanism / How it works

Three-tier argument · why it is not an FX business:

  1. An individual / company voluntarily exchanges 2 independent 1:1 stablecoins with each other = voluntary asset allocation · no FX license required
  2. The DEX provides pool liquidity = automated market-making · not an OTC FX desk
  3. Mint/burn is performed only by the issuer = what the issuer does is “redemption” · not “exchange”

This entire structure is simultaneously legal under the three frameworks of GENIUS §501 + MiCA Title IV + the Japan PSA, but · it collapses upon a regulatory redefinition in any one of them.

Why §501 left room: the main constraint of the GENIUS Act §501 = a payment stablecoin must be 1:1 fiat-reserved · the issuer must be an IDI / NCBA / QC NTI · direct conduct of FX business is not permitted (to avoid a conflict with ECF 1934 regulation). But it does not state that “a swap of 2 independent stablecoins = FX” → a legal vacuum.

MiCA’s active encouragement: Title IV (EMT) permits multiple issuers · reduces single-dependence on Circle · the EU actively leaves room for on-chain FX liquidity (the political intent = reducing dependence on USD-stablecoins).

Origin & evolution

Before 2024 年 = on-chain FX was not feasible (USDC dominance). 2024 MiCA Title IV took effect + EURC circulation rose + the listings of SocGen / Lugh = a multi-issuer structure on the euro side was formed. 2025 JPYC became the first yen stablecoin under the new framework of Japan’s Payment Services Act. 2026.05 triangular arbitrage went into actual operation on a DEX for the first time = the legal hack moved from theory to product.

Sources

  • GENIUS Act §501 / MiCA Title IV / Japan PSA (2023 amendment)
  • SEC Uniswap Wells Notice (2024)