Gateway buyers stepped down one price tier, not to the floor, loosening the Anthropic-gets-the-money consensus. In Vercel's leaderboard export (spend is a list-price-weighted estimate, not billing), Anthropic's spend share fell from a 63.5% August daily average to a 38.0% seven-day average (Sep 22 to 28); Sep 28 rebounded to 43.4%. The Opus 5.5 price cut explains at most 4 points (author's calculation). Moonshot rose from 4.5% to 14.7% and OpenAI from 13.2% to 22.3%.
Investors: gateway share is not Anthropic revenue; among Chinese models, back those paid above $10/M output, not the cheapest.
Founders: agent workloads move first; post-train an open base as Harvey did to rescue gross margin (margins per Bloomberg, citing people familiar).
Falsifier: by 2026-12-31, any 30-day Anthropic spend share average of 53% or more marks this wrong and 40% or less verifies it, recomputed from Vercel's labs export with the repo script (Aug 30 to Sep 28: 46.4%).
Ledger update (Oct 2): Anthropic's 30-day spend share is 44.8% and Kimi K3's is 10.4%, inside all four falsifier lines; Kimi K3 fell to 5.0% on Oct 1 with no first-hand explanation, so no attribution.
Disclosure: written and checked with Claude tools; Anthropic is in direct conflict with Moonshot; FutureX holds Hugging Face, ByteDance and Mistral (an earlier version also listed Meituan, with an indirect Moonshot interest, and Xiaomi; the author confirmed on Oct 10, 2026 that FutureX has fully exited both); the author is a Vercel customer.
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