Overnight: Seoul takes the hit

The first signal came from Asia. South Korea's KOSPI dropped more than 5% in one report and about 6% in a later one, led by Samsung and SK Hynix. The trigger was an announcement from Chinese memory maker CXMT about a more efficient chip design, on top of capital-spending warnings from industry leaders. In New York, memory and optical-networking names such as Coherent, Lumentum and Applied Optoelectronics extended their losses before the bell, and the Nasdaq-100 pointed lower.

Behind the price action sits a bigger worry. Broadcom CEO Hock Tan said access to capital could be a tougher bottleneck for AI infrastructure than chip or power supply, and Intel's CEO questioned the borrowing costs and returns on AI spending. Cerebras fell to a new 52-week low ahead of a lockup expiry on Wednesday, and Nvidia's share of China's data-center AI chip market reportedly slipped to 34% in the first half as Huawei gained ground.

Before the bell: the banks report

JPMorgan earned $15.3 billion, or $5.57 a share, against about $5.90 expected. Investment-banking fees came in at $3 billion, up 14% from a year earlier but down 8% from the prior quarter. CFO Jeremy Barnum said deals are more likely "delayed rather than canceled." Goldman Sachs reported a 29% profit increase and rose more than 4% premarket, and Wells Fargo beat expectations. Elsewhere, UnitedHealth raised its 2026 profit forecast and gained about 3%, while Johnson & Johnson beat and raised guidance but slipped on soft medical-device sales.

The number everyone is waiting for

Wednesday's September CPI will say whether inflation is cooling enough for the Fed to stand still after last month's hike, its first since 2023. Consensus is a 0.6% monthly rise, with core at 0.2% and annual headline inflation around 3.6% to 3.7%. Cleveland Fed President Beth Hammack has already said more tightening may be needed. With the 10-year yield near a 24-year high, a hot print would hurt valuations that are already under question.

The stories behind the moves

Goldman's 29% profit jump and UnitedHealth's raised outlook explain the gains at the top. Visa edged up after China approved preparations for a domestic bank-card clearing business, and Navitas rose after unveiling a 24kW power board developed with Nvidia. Six Flags fell after a guest died on a roller coaster in Georgia, and Samsung and SK Hynix paid for the CXMT news.

Also on the tape

Cerebras hit a new 52-week low ahead of Wednesday's lockup expiry. Optical-networking names Coherent, Lumentum and Applied Optoelectronics kept falling. Johnson & Johnson beat estimates and raised guidance, yet traded lower on weak medical-device sales, a reminder that the market now reads the details, not just the headline beat.

How to read a list like this

Premarket moves are thin-volume moves. A stock that jumps 4% before the open can fade by the first hour. Treat these as a map of where the news is, then check what the stock does once real volume arrives.