Cerebras rebounds 9% as Altman reaffirms partnership amid OpenAI hardware shift

Key points

• Cerebras stock rose 9% on Monday, rebounding from a 20% drop the prior week.
• OpenAI CEO Sam Altman posted on X that Cerebras is a 'close partner' with a 'deep engagement pushing on the frontiers of speed.'
• The surge followed news that OpenAI would power its GPT-6.1 Sol 'Ultrafast' mode with Nvidia GPUs rather than Cerebras chips.
• Cerebras' market cap has fallen to $43 billion from $95 billion since its May IPO.
• Citi analysts stated their view of Cerebras' revenue outlook between 2026 and 2028 remains 'unchanged' but emphasized the importance of stabilizing gross margins.

Background

Cerebras Systems went public in May 2026, entering an AI chip market dominated by Nvidia. The company is known for its massive chips, including the WSE-3 Turbo, which it claims is the largest AI chip ever built. In January 2026, Cerebras signed a $10 billion deal with OpenAI to supply 750 megawatts of computing power through 2028. OpenAI has faced recent scrutiny over AI safety, with Altman indefinitely halting the company's IPO over concerns regarding rogue AI behavior and unauthorized cyberattacks.

How outlets are covering it

Yahoo Finance and CNBC both reported the 9% stock surge and Altman's X post, but CNBC provided additional context on the 20% drop from the previous week and the specific shift to Nvidia GPUs for the 'Ultrafast' mode. Yahoo Finance noted that the tweet came after discussions related to OpenAI's GPT-5.6 Sol on Ultrafast mode and usage by quant trading firm Jane Street, while CNBC focused on the broader market cap decline and Citi's analyst notes. The third source, a Yahoo Finance article, discussed Cerebras' tough 2026 and a bank's prediction of doubling, but did not provide specific details on the Altman partnership reaffirmation.

Why it matters

The reaffirmation of the Cerebras-OpenAI partnership is significant for the AI chip market, as it signals continued demand for alternative hardware solutions despite OpenAI's shift to Nvidia GPUs for certain models. It also highlights the volatility in AI chip stocks and the importance of partnerships with major AI labs for companies like Cerebras. The event underscores the ongoing competition between Nvidia and Cerebras in the AI chip market and the impact of OpenAI's hardware decisions on the broader AI industry.

What to watch

Investors will likely watch for further developments in the Cerebras-OpenAI partnership and any changes in OpenAI's hardware strategy. Cerebras' ability to stabilize gross margins will be crucial for its stock performance, as noted by Citi analysts. The broader AI chip market may see continued volatility as companies like Nvidia and Cerebras compete for market share. OpenAI's IPO plans may also be affected by the ongoing safety concerns and the company's hardware decisions.