A surge of concerns has hit Cerebras shareholders following reports that the firm's chips are absent from OpenAI's latest model. The chief financial officer and head of accounting have both offloaded their equity in the AI hardware maker, joining the chief operating officer in a series of high-level exits. This divestment coincides with reports that the new GPT-6.1 Ultrafast does not use Cerebras Wafer Scale Engines, despite the company having praised its role in GPT-5.6 Sol Ultrafast last month.

Chief operating officer Dhiraj Mallick liquidated his shares on September 29, selling $78 million to leave himself with zero stake in the company. While analysts and investors have called for transparency regarding the claims reported by SemiAnalysis, Cerebras has remained silent on both the status of its hardware in the latest OpenAI model and the timing of the insider sales.