Shares of AI chip maker Cerebras fell sharply Monday to around less than half of its closing price when it first started trading in May. Once one of 2026's hottest initial public offerings, surging nearly 70% on its opening day, the stock is now struggling.

The AI chip maker is heavily reliant on selling its wafers to OpenAI, which is said to be leaning into Nvidia chips for its latest GPT6.1 Sol AI model. Plus there's a broader downturn in the chip sector, in general. The iShares Semiconductor ETF was down 2% on Monday. Cerebras stock was down 10% in Monday trading, and shares of other chip makers such as Nvidia, Micron, and AMD were trading lower, too.

The sector has been under pressure following a report late last week that OpenAI's recurring revenue may fall short of what many were expecting. That raises concerns that the market may be softer than anticipated.

Cerebras is particularly exposed to any potential weakness from OpenAI because it is the chip maker's biggest customer by revenue backlog, a term that refers to the amount of contracted orders. At the end of last year, Cerebras had a backlog of $24.6 billion, with $20 billion of that tied to a deal with OpenAI.

Cerebras stock recently got a bounce earlier this month when OpenAI CEO said the maker of dinner-plate sized AI chips was a "close partner," amid the concerns about Nvidia chips.

But that bounce was short lived. Its stock price is now on track for its lowest close on record, trading around $148.07 by midday.