Why Cerebras Stock Is Falling Below Its $185 IPO Price in…
By Tobi Opeyemi Amure
AI summary of the source article
Cerebras Systems stock dropped 13.0% across two trading sessions, closing at $169.52 on October 1, 2026, well below its $185.00 IPO price. The sell-off was triggered by reports citing a SemiAnalysis post on X claiming that OpenAI's GPT-6.1 Sol Ultrafast tier operates on Nvidia GPUs at a low batch size instead of Cerebras chips. Concurrently, COO Dhiraj Mallick sold 396,000 shares under a pre-established Rule 10b5-1 plan. Cerebras still notes on its website that it powers an earlier tier, GPT-5.6 Sol Ultrafast, and neither OpenAI nor Cerebras has officially confirmed any hardware shift regarding GPT-6.1.
Why it matters
The reported hardware shift could impact Cerebras's revenue for that specific tier, though it does not cancel the company's December 2025 contract for 750 megawatts of capacity.
Key facts
- Cerebras stock closed at $169.52 on October 1, 2026, down 8.4% from its $185.00 IPO price.
- Media reported a SemiAnalysis post claiming OpenAI's GPT-6.1 Sol Ultrafast tier runs on Nvidia GPUs instead of Cerebras chips.
- COO Dhiraj Mallick sold 396,000 shares on September 29 under a Rule 10b5-1 plan adopted June 30, 2026.