Cerebras Shares Fall Nearly 20% in a Week, Closing at a Post-IPO Low

Cerebras finished October 2 at $166.43, its lowest closing price since its May IPO, after losing nearly 20% in a week. The slide came as insider share-sale restrictions expired and a report that Nvidia would power an OpenAI workload challenged the company’s pitch as an alternative to the AI chip giant.

The retreat has taken Cerebras shares down by more than half from their post-IPO opening price. Its May debut had put the company’s market value close to $100 billion; by Friday, that valuation was just over $39 billion, according to CNBC.

Cerebras sells a different approach to running AI models. It makes dinner plate-sized custom chips designed for inference—the computing used to produce a model’s answers—and offers access to that hardware as a cloud service from its own data centers.

OpenAI is central to that commercial story. In January, Cerebras struck a deal worth more than $10 billion to supply OpenAI with 750 megawatts of computing power through 2028. That agreement gave the hardware challenger a large commitment from a major AI customer, rather than just a promise of competing with Nvidia.

The immediate competitive concern is narrower than that agreement. CNBC cited a September 30 X post by research firm SemiAnalysis saying OpenAI would use Nvidia graphics processing units, or GPUs, instead of Cerebras hardware for GPT-6.1 Sol’s “Ultrafast” mode. That is attributed reporting about a specific workload, not a confirmed OpenAI announcement about the broader computing deal.

The same week brought a separate pressure on the stock: the end of restrictions that had prevented some holders from selling after the IPO. CNBC reported, citing Cerebras’s prospectus, that up to 19.4 million shares unlocked on September 30, equal to 8% of all shares outstanding.

The newly eligible shares belonged to directors, officers, non-executive employees and other holders. They followed earlier releases of up to 14.6 million shares every two weeks since August 19. These are eligibility figures: the expiration of a restriction permits a sale, but does not mean every unlocked share was sold.

Actual executive sales were already substantial. CEO Andrew Feldman and CTO Sean Lie sold more than $240 million of Class A shares between August 20 and September 25. Those sales took place under trading plans adopted shortly after the IPO—a different timeline from the SemiAnalysis post that accompanied this week’s competitive concerns.