Cerebras Stock Falls Below $185 IPO Price Amid GPT-6.1 Nvidia-GPU Claim

Cerebras Systems Inc. (NASDAQ: CBRS) shares fell over 7% to $181 in afternoon trading on Wednesday, pushing the AI-chip maker below the $185 price of its May initial public offering. 

The stock was trading amid a SemiAnalysis social-media claim that a GPT-6.1 Sol Ultrafast implementation was running at low batch size on Nvidia GPUs rather than Cerebras hardware. OpenAI’s September 29 materials said Sol Ultrafast was coming soon, while GPT-6 Astra Ultrafast was already available.

Neither OpenAI nor Cerebras had publicly confirmed which hardware would serve GPT-6.1 Sol Ultrafast. OpenAI had previously said its GPT-5.6 Sol Ultrafast preview was powered by Cerebras.

Separately, two Form 144 notices covering proposed stock sales by Cerebras officers valued at a combined $84.3 million appeared on EDGAR shortly after Tuesday’s regular trading session ended. Form 144 reports proposed sales, so the filings do not show that all of the listed shares were ultimately sold.

In addition, up to approximately 19.4 million Cerebras shares held by directors and officers, non-executive employees and non-employee holders became eligible for sale at 6:00 a.m. ET Wednesday under the company’s IPO lock-up schedule. The schedule does not show that any of those shares were sold, and any sales remain subject to applicable restrictions.

Mallick and Komin Notices Cover 428,500 Shares

Chief Operating Officer Dhiraj Mallick’s notice covers 396,000 shares with an aggregate market value of $77.91 million and lists September 29 as the approximate sale date. Of those shares, 276,000 are tied to the exercise of stock options and 120,000 to performance stock units.

Mallick’s filing also reports an August 18 sale of 38,889 shares for gross proceeds of about $8.64 million.

Chief Financial Officer Robert Komin filed a separate notice covering 32,500 shares valued at $6.39 million, also with September 29 as the approximate sale date. The shares came from stock options that had been exercised in August 2024.

Both filings list June 30, 2026, as the date of plan adoption or trading instruction for purposes of Rule 10b5-1. Cerebras’ second-quarter filing also lists June 30 as the adoption date for trading arrangements covering both Mallick and Komin. The plans therefore predate Wednesday’s share-price decline.

Meanwhile, Cerebras Systems Tokenized Stock (CBRSon), an Ondo tokenized product providing economic exposure similar to CBRS, was trading at $181.17, down 14.34% over the previous 24 hours, according to CoinMarketCap.