Cerebras Systems (CBRS) stock fell 57.6% from August 4 to November 2, 2026, while the S&P 500 lost 2.3%, according to the article. Shares slid following the company’s August 12 second-quarter report and dropped again in late September and early October as reports said Cerebras lost an OpenAI workload to Nvidia. Cerebras had $25.4 billion of contracted work still to deliver at June 30, and management said none of it came from AWS or any other large cloud provider; September news reports said a significant amount of that backlog traces to a December agreement with OpenAI. Management said OpenAI will still be a meaningful portion of revenue in 2027, shrinking over time as AWS and other customers grow. News reports that week, including on October 2, said Cerebras lost a key workload for OpenAI’s Ultrafast mode to Nvidia during the same week a lockup on early holders’ shares expired. On October 5, OpenAI’s chief executive called Cerebras a close partner, and the shares rose 11% in early trading, but they still lost 42.1% between October 2 and November 2. Late in October, short seller Culper Research disclosed a position against Cerebras, and the shares fell 11.7% to a record low on November 2. Cerebras reported revenue of $180 million for the quarter ended June 30, up from