Anthropic’s October 26 S-1 filing named Goldman Sachs in the lead-left underwriting position, directly driving the 95.7% market-implied probability and collapsing prior speculation around Morgan Stanley. This placement, which traditionally confers primary responsibility for pricing, roadshow coordination, and syndicate management, aligns with Goldman’s identical role on the recent SpaceX IPO and reflects established relationships plus execution track record in large technology offerings. The filing’s explicit hierarchy has produced broad trader consensus, with real capital now concentrated behind the disclosed structure. A realistic shift would require a subsequent amendment altering the underwriting order or redefining the lead role, though such changes remain uncommon once the prospectus is public.