Cerebras stock hits post-IPO low, tumbling 20% for the week on Nvidia pressure and lockup expiration

Cerebras stock plummeted nearly 20% this week to its lowest price since the company’s monster IPO in May, after a report that chip giant Nvidia will power a crucial piece of OpenAI’s latest model.

Research firm SemiAnalysis posted on X on Wednesday that OpenAI will power its “Ultrafast” mode for GPT-6.1 Sol with Nvidia graphics processing units instead of Cerebras hardware. Cerebras shares are now down by more than half since their initial pop that followed the company’s debut on the Nasdaq.

The stock, which closed on Friday at $166.43, was also under pressure this week due to the expiration of post-IPO restrictions on some insider shares.

However, it rose almost 3% in extended trading on Friday after OpenAI CEO Sam Altman responded to the “speculation about our partnership with Cerebras.”

“Cerebras is a close partner, and we have a deep engagement pushing on the frontiers of speed,” Altman wrote in a post on X.

Still, it’s been a brutal stretch for Cerebras, which closed at a $95 billion market cap on the first day of trading, just shy of joining the ranks of Meta, Alibaba and now SpaceX, which closed their initial day with valuations over $100 billion.

Cerebras’ market cap now sits at just over $39 billion.

Investors were excited by…