Markets NVDA +0.25% JUL 28, 2026

Nvidia's $250B OpenAI backstop triggers global chip rout — NVDA −5%, KOSPI circuit-breaks on 10.84% plunge

Samsung fell 13.4% and SK Hynix 14.65% as Seoul halted trading twice; 'round-tripping' concerns now shadow Nvidia's guarantee for OpenAI's 10-gigawatt Ohio build.

BY HENLEY MARRAST · MARKETS DESK

The KOSPI closed down 10.84% at 6,023.66 on Tuesday, its worst session since March, forcing Korea Exchange to trigger a marketwide circuit breaker for the eighth time this year and the 14th in the index’s history. Cash trading on the KOSPI and Kosdaq was halted for 20 minutes each after futures collapsed, according to Bloomberg. The immediate catalyst sat 7,000 miles away: Nvidia’s reported $250 billion financing guarantee for OpenAI’s 10-gigawatt Ohio build.

Samsung Electronics shed 13.39% to 220,000 won. SK Hynix fell 14.65% to 1.55 million won. SK Square dropped 15.6%, Hanmi Semiconductor 12.22%. Nvidia itself was down roughly 5% in New York after CNBC confirmed the Wall Street Journal report a day earlier.

The structure of the deal is what spooked the tape. Reuters framed the arrangement as OpenAI’s exit from dependence on Microsoft, Amazon and Oracle capacity, with Nvidia locking in years of GPU demand it’s now underwriting itself. The WSJ pegs the full project above $500 billion including silicon, with an 800-megawatt first phase due in 2028 and SoftBank’s SB Energy on power. U.S. Commerce Secretary Howard Lutnick is arbitrating site access, with Anthropic, Microsoft and Google also in the room.

Investors have a word for a vendor guaranteeing its largest customer’s purchases of its own product. That word is round-tripping, and it hasn’t been this legible in a semiconductor cycle since the fiber-optic vendor financing of 1999–2001, when Lucent and Nortel booked revenue against loans they’d extended to the carriers buying the gear.

Kim Seok-hwan of Mirae Asset Securities put it dryly: “A new shock didn’t bring the market down. It was familiar risks finally being priced in as crowded positioning met thin liquidity.”

Familiar is doing a lot of work in that sentence. The KOSPI is down 29% in July, exceeding the 27% monthly record set in October 1997, and roughly 45% off its June 22 peak of 9,114.55. AI infrastructure spending is on track to exceed $700 billion this year. Seoul is where that number gets marked to market first, and today it did.

Sources

About the author

Henley Marrast

MARKETS DESK

Henley Marrast covers AI-equity flow, accelerator demand, and earnings prints for AI Sheet Report. She leads coverage of the public AI complex from the New York markets desk, with a focus on the daily tape and quarterly results. She has been writing about technology markets for several years.