Cerebras Systems Inc. (NASDAQ:CBRS) shares are trading lower Wednesday as a new wave of shares hits the market. There are also reports that OpenAI’s newly unveiled GPT-6.1 Sol Ultrafast is not running on Cerebras hardware.

Major Share Unlock Wave Hits the Market

Cerebras’ IPO lockup isn’t a single 180-day freeze — it releases shares in 11 separate waves rather than all at once. A wave of smaller 14.6 million-share unlocks started in August, with 14.6 million share blocks being released for trading three separate times.

Wednesday’s release frees approximately 19.4 million shares for trading, one of three larger waves on the schedule, with the other two falling on Oct. 14 and Oct. 28. Those three releases alone are set to free about 58 million additional shares for public trading.

The entire schedule fully expires no later than Nov. 9, 180 days after the IPO prospectus date, or two trading days after Cerebras reports third-quarter earnings. Cerebras stock is currently trading below its IPO price of $185.

GPT-6.1 Sol Ultrafast Reportedly Runs on Nvidia

Separately, OpenAI unveiled GPT-6.1 Sol at its DevDay event on Tuesday, positioning it as a model that nearly matches its flagship GPT-6 Astra on agentic coding, computer use and professional work at roughly a fifth of the price.

According to a post from SemiAnalysis, the model’s Ultrafast speed tier is running on Nvidia GPUs this time around rather than Cerebras chips. Neither OpenAI nor Cerebras has publicly confirmed which hardware serves the new tier.

Cerebras Shares Fall

CBRS Price Action: At the time of publication, Cerebras shares are trading 5.76% lower at $183.85, according to data from Benzinga Pro.

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