OpenAI Bought 4.22% of Cerebras Before Selling You Cerebras Speed

OpenAI exercised every vested warrant share it held in Cerebras Systems in July, taking a 4.22% economic stake in the chipmaker, and the launch post for the Cerebras-powered Ultrafast tier a day later did not mention it ^[1][2]. Cerebras put the transaction under "Subsequent Events" on page 29 of a quarterly filing released after the market closed on August 12th; the GPT-5.6 Sol Ultrafast limited preview opened on August 13th ^[3][4][4].

The mechanics are small numbers attached to a large one. OpenAI exercised warrants for 10,033,508 Class N shares at a contractual price of $0.00001 each, a cash cost of about $100.34 ^[5]. Those shares were 4.22% of the 237,564,041 shares outstanding as of August 5th ^[6]. Marked against Cerebras Class A stock at roughly $229 on Thursday afternoon, the position carried an implied value of about $2.3 billion, though that is a mark on a traded Class A price rather than a liquid Class N security ^[7][8]. The paper position is on the order of 23 million times the cash paid for it ^[1]. Class N carries the same dividend and liquidation rights as Class A and Class B, no votes, and generally converts one-for-one on transfer, so OpenAI holds the economics without a say over the board ^[9][10].

The warrant comes from the December 2025 master relationship agreement, under which OpenAI committed to 750 megawatts of inference capacity in tranches through 2028 with an option for another 1.25 gigawatts by the end of 2030, two gigawatts in total if fully taken ^[11][12][5]. OpenAI also extended roughly $1 billion in secured working capital in January ^[13]. The full warrant covers 33,445,026 Class N shares; 4,459,337 vested in January once the loan was funded and 5,574,171 vested in June, exactly the total exercised, and none had been exercised as of June 30th ^{[14][15][16][17]}.

That leaves 23,411,518 shares, vesting on milestones tied to committed and additional capacity, market capitalization or customer payments ^[18][3]. Full vesting and exercise would put OpenAI at about 12.8% on the current share base for roughly $234 in exercise cost ^[19][20]. Read plainly: OpenAI's ownership increases as OpenAI buys more Cerebras compute, and Cerebras shareholders absorb the dilution if the relationship works ^[21]. Cerebras values the warrant at $82.02 per share as granted and records the customer warrant asset as a reduction in revenue across the life of the relationship, booking $822.9 million in the first half of 2026 ^[22][23], which is within rounding of the exercised shares at the grant value ^[2].

For anyone pricing Ultrafast, the performance claims are still OpenAI's own. OpenAI says the tier runs GPT-5.6 Sol at up to 750 output tokens per second and up to 14 times its Standard tier, a comparison against its own baseline ^[24][25]. The 750 figure measures output generation and does not establish time to first token or the duration of a workflow that calls tools ^[26]. Early testers include Jane Street, Podium, Basis and Rogo, and Podium product lead Courtland Lykins said the speed "completely changes the call experience" for complex work ^[27][28]. Cerebras shares traded lower on August 13th, which the filing-based reporting notes does not establish how investors read the partnership ^[29][30].

Watch the next Cerebras filing for whether additional tranches move to probable; the ones tied to additional capacity were not probable as of June 30th ^[31]. Watch whether Ultrafast pricing and general availability follow, and whether latency data comes from anyone who does not hold the equity.