A single vendor termination just wiped 88% off a stablecoin that called itself institutional-grade

MainStreet's msUSD stablecoin collapsed 88% on June 20, 2026 after verification provider Accountable terminated its service agreement, instantly destroying the market's ability to confirm the token's reserves. The crash reveals how yield-bearing stablecoins can carry structural fragility that standard reserve-disclosure rules, including those in the GENIUS Act, don't yet require issuers to disclose.