Cerebras Shares Rebound After Altman Addresses OpenAI Partnership

Cerebras Systems Inc. shares moved sharply after reports questioned the hardware used for OpenAI’s newest model tier, with the stock later rebounding after OpenAI CEO Sam Altman addressed the partnership between the companies. The developments involved Cerebras, OpenAI, and Nvidia-related chip reports.

According to TradingView, Cerebras shares fell on September 30 after SemiAnalysis reported that OpenAI’s GPT-6.1 Sol Ultrafast tier was running on Nvidia GPUs instead of Cerebras hardware. Neither OpenAI nor Cerebras confirmed the hardware supporting the new tier.

TradingView reported that Cerebras had powered the previous GPT-5.6 Sol Ultrafast tier, which reached speeds of up to 750 tokens per second starting in August. The company’s shares closed Friday at $166.43, below its $185 initial public offering price.

Altman responded to speculation about the companies’ relationship after the share decline. The OpenAI CEO described Cerebras as a partner while discussing the ongoing collaboration.

"close partner" said Sam Altman, OpenAI CEO.

Altman posted on X on October 2, saying the message did not identify which chips were being used for GPT-6.1 Sol Ultrafast. His statement focused on the broader relationship between OpenAI and Cerebras.

"There is some speculation about our partnership with Cerebras. Cerebras is a close partner, and we have a deep engagement pushing on the frontiers of speed." said Sam Altman, OpenAI CEO.

TradingView reported that Cerebras shares rose about 9% on October 5 after Altman’s post. Barclays analyst Tom O’Malley also assessed the relationship between the companies.

"remains strong" said Tom O’Malley, Barclays analyst.

At the time of publication, Benzinga Pro data cited by TradingView showed Cerebras shares trading 1.56% lower at $161.61.