Open-weight models take 56% of token volume, Astra doubles Fable 5.1 spend
Source
Amelia Charles
Author
Amelia Charles
Date
Key takeaways · AI-distilled
open weightsA model whose trained parameters are published for anyone to download and run — unlike API-only models you can access but never possess.Full definition → models ran the majority of AI Gateway tokenThe chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.Full definition → volume for the first time in August 2026 — 56%, up from just 7% in December 2025 — even as frontier labs kept most of the dollar spend.
Average price per token on the gateway fell 23.2% in August, the third straight monthly drop, and teams running over 10 million tokens paid a median 7.6% less per token than the prior month, more than double July's 2.9% decline.
Nine in ten teams using Claude Fable 5 cut their usage after Opus 5 (half of Fable's price) launched, and most of that spend moved to Opus 5 rather than a rival lab — so Anthropic kept roughly 61-64% of all gateway spend every month since December despite the churn.
GPT-6 Astra took a third of OpenAI's own gateway spend within two days of its September 3 launch, and over each model's first twelve days it out-earned Anthropic's Fable 5.1 more than 2x in gateway spend share (7.7% vs 3.7%).
Google's Gemini 3 Flash lost 95% of its gateway token share since May, split roughly evenly between cheaper models (led by GPT-5.6 Luna) and pricier ones (led by Claude Opus 5 and Sonnet 5) — pushing Google's total gateway token share from 30% to 5%.
Terms in this piece · Glossary
open weights — A model whose trained parameters are published for anyone to download and run — unlike API-only models you can access but never possess.
token — The chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.
Why it matters
Concrete usage data showing the market is shifting fast toward cheaper open-weight models and newer flagship releases, useful for anyone deciding what to build against or budget for.
