AI Insiders reported on 15 August that OpenAI had put GPT-5.6 Sol on Cerebras silicon for up to 14 times the speed of its standard tier, in a limited preview called Ultrafast. A filing that surfaced two days before that preview explains the financial relationship sitting underneath the hardware deal. OpenAI already owns a meaningful slice of the chipmaker that runs it.
Implicator.ai reported the filing on 15 August, two days after the Ultrafast preview went live. The number generating headlines is the price OpenAI paid: about $100 in cash. That figure describes a strike price, not a purchase price. In July, OpenAI exercised warrants it had already earned under an agreement struck in December 2025, acquiring 10,033,508 Class N shares of Cerebras at a contractual $0.00001 apiece.
Warrants of this kind are ordinary in supplier relationships. A chip maker grants the right to buy shares cheaply as an incentive tied to a customer’s spending commitments, and the customer exercises that right once it vests. OpenAI was not shopping for a bargain. It was collecting on a deal it struck months earlier.
At a Class A share price near $229 on 13 August, the stake carries an implied value close to $2.3 billion. That mark applies to Class A stock; OpenAI’s holding sits in Class N shares, which are not liquid, carry no voting rights, and generally convert to Class A only when transferred. The resulting 4.22 percent stake is calculated against 237,564,041 Cerebras shares outstanding on 5 August.
That warrant sits inside a larger supply agreement. OpenAI is contracted to draw 750 megawatts of Cerebras inference capacity across tranches running through 2028, and can add as much as 1.25 gigawatts more before 2030 closes. A roughly $1 billion secured working-capital loan in January triggered the first tranche of warrants. OpenAI still holds warrants tied to future capacity growth, payments, and valuation triggers, covering another 23,411,518 shares.
The capacity secured under that agreement is what now runs Ultrafast, the preview OpenAI announced on 13 August. Ultrafast is not a new model. It is GPT-5.6 Sol running on Cerebras wafer-scale chips, advertised at as many as 750 output tokens per second, or roughly 14 times what OpenAI’s Standard tier delivers. Cerebras says its wafer-sized chips hold 44 gigabytes of on-chip memory, keeping model weights close to the processor instead of shuttling them to external storage between tokens.
Every competitive comparison behind that speed claim came from Cerebras, not an independent evaluator. The company said Ultrafast finished the 2,500-question Humanity’s Last Exam in just over eleven hours on 10 July, versus roughly 78 hours for Anthropic’s Claude Fable 5, measured across three days in mid-July using a different software harness. Cerebras framed the outcome as nearly seven times quicker at similar accuracy, though it withheld the actual accuracy numbers. OpenAI has not disclosed pricing, a distinct model identifier, or a general-availability date for Ultrafast.
This account rests on Implicator.ai’s 15 August reporting and its reading of the quarterly filing; no other outlet had independently corroborated the figures at publication. The tension worth naming plainly is straightforward: OpenAI took an equity stake, worth far more than its $100 strike cost, in the supplier whose chips power its fastest sales pitch, and that stake became public two days before the pitch. Nothing here indicates wrongdoing. The warrants predate the Ultrafast preview by months, and Cerebras’s speed claims stand or fall on their own regardless of who owns what.
Enterprise buyers evaluating Ultrafast should ask for a benchmark run outside Cerebras before committing workloads to the tier, since every published number so far comes from the hardware vendor itself. Anyone tracking Cerebras as an independent chip supplier should also watch how OpenAI’s economic stake in the company shapes capacity allocation once the remaining 23.4 million warrant shares vest.
Implicator.ai reported this story on 15 August 2026, based on a Cerebras quarterly filing disclosed 12 August.
