Does The Fall In Cerebras Stock Change Anything?
Cerebras Systems (CBRS) stock fell 19.5% between September 25 and October 2, 2026, while the S&P 500 slipped 0.2%. The fall came in a week of news reports about the company’s work for OpenAI. What did Cerebras reportedly lose at OpenAI, and which part of its business is tied to that one customer?
Cerebras Reportedly Lost An OpenAI Workload To Nvidia
Cerebras lost a key OpenAI workload to Nvidia, CNBC reported on October 2, 2026. The work was for the “Ultrafast” mode of one of OpenAI’s AI models. By October 1, a report had questioned whether Cerebras’s anchor customer moved its fastest model to rival hardware. Insiders had also filed to sell shares by then, and a lockup on the stock expired during the week.
The sharpest single session came on September 30, when Cerebras stock fell 8.9%. Barron’s reported that day that the stock fell again because so much depends on OpenAI. Cerebras fell alone, not with chip stocks as a group: Nvidia stock rose 3.9% over the same week.
Cerebras’s Cloud Growth Is Tied To OpenAI
Cerebras sells hardware, and it also rents out its computing power as a cloud service. In the second quarter of 2026, cloud and other services brought in $127.7 million of the $209.9 million the company calls core revenue. Cloud revenue was up 287% from a year earlier, against 17% for hardware. Management said on its August 12 call that cloud revenue rose because its OpenAI deployment grew and other cloud customers used more of the service.
So the reported loss is in the side of Cerebras that was larger and grew faster in the second quarter. That matters for 2027, when management expects core revenue to more than triple and OpenAI to remain a meaningful portion of it. Cerebras now faces a question over how large OpenAI stays.
Cerebras Expects Its Service On AWS In 2027
Cerebras expects its service to be generally available through AWS in the first quarter of 2027. Customers it gains there would make OpenAI a smaller share of its revenue. Cerebras had $25.4 billion of contracted work still to deliver on June 30, 2026, but management said none of it came from AWS or other large cloud companies.
One new name did arrive during the fall: Reuters reported on September 28 that Cerebras plans to supply AI chips and hardware to the cloud startup Gimlet Labs.
Cerebras Still Loses Money And Trades Far Above Sales
After the fall, Cerebras stock still trades at 43.6 times sales, against 3.0 for the S&P 500, and that price appears to assume the 2027 growth arrives. The fall did not change Cerebras’s losses either: its operating loss over the past twelve months was about as large as its revenue. The company has no earnings, so a P/E is not meaningful.
Cerebras also still has cash. It ended the second quarter with more than $8.6 billion in cash, restricted cash and marketable securities.
On August 12, before the reports about OpenAI, management guided third-quarter core revenue to $214 million to $216 million. The Q3 2026 report is the first place to check whether the reported loss of OpenAI work has reached Cerebras’s sales.
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