Contagion through Opacity: Design and Survival in the November 2025 Stablecoin Cascade

In early November 2025 the yield-bearing stablecoin sector experienced its first systemic run: over roughly seventy-two hours, three synthetic dollar tokens lost between 94 and 99 percent of their value, set off by the disclosure of an external-manager loss at Stream Finance. Using hourly on-chain data we reconstruct the cascade and show that survival was not determined by on-chain exposure or scale-the largest instrument, sUSDe, held its peg while absorbing several hundred million dollars of redemptions-but by the quality of the backing and whether redemptions were honored under stress. We further show that the contagion did not travel through observable decentralized-finance composability: public lending exposure to the failed collateral was negligible.

Transmission ran instead through off-chain reserve relationships and, in the single material public exposure, through a price oracle that remained frozen at the pre-crash value, implying a roughly 119-fold overvaluation weeks into the collapse, so that no liquidation fired and approximately $7.5 million of bad debt accrued without a single onchain bad-debt event. We read the episode as evidence that opacity in valuation, rather than composability, was the systemic channel, and draw implications for the disclosure, redemption, and oracle requirements that govern tokenized dollars. The paper is a descriptive and structural anatomy of one systemic episode; we make no causal-identification claim.