Brockman Implies o1, o3, GPT-5 and GPT-5.1 All Built on the Same GPT-4o Base

scaling01 · x · 2026-09-03

OpenAI president Greg Brockman said that from GPT-4o's April 2024 launch to December 2025, the company was "really squeezing the juice out of the GPT-4o model," implying o1, o3, GPT-5 and GPT-5.1 all share the same underlying base model and pre-training. scaling01 speculates GPT-5.2 may be a different model — the one behind OpenAI's price hike to $14.

Related event: Brockman Suggests o1/o3 and GPT-5 Are Built on GPT-4o(2 posts)→

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