The 2026 AI-adjacent mega-IPO cohort is losing its post-listing premium: SpaceX (SPCX) broke below its $135 IPO price for the first time; SK Hynix's US ADR ($26.51bn — largest-ever foreign US listing) trades ~50% above its Seoul shares, a 'Law of One Price' violation that can't yet be arbitraged (non-fungible listings). Cerebras/CoreWeave in the same bucket. Mechanism: post-IPO froth deflating is a sentiment/positioning gauge for the broader momentum-factor unwind; feeds the ES/Nasdaq vol-building narrative. No clean primary-tier futures proxy; bears on ES via sentiment.