KOSPI AI selloff deepens as Seoul index drops about 5%

Asia's AI trade cracked hardest in Seoul. The KOSPI AI selloff left the benchmark down 311.84 points, or 5.25%, at 5,626.02 late Friday morning after Wall Street's tech rout spilled into chipmakers.

What happened

Yonhap said the index opened 2.99% lower and kept falling as Alphabet's 12.6% drop, Amazon's after-hours slide and Intel's more than 20% plunge overnight revived questions about AI returns. The Korea Exchange triggered a sell-side sidecar for five minutes after the KOSPI 200 futures index fell 5% or more for at least a minute, the first such halt in 11 sessions.

Samsung Electronics fell 6.03% and SK hynix plunged 8.65%. Hyundai Motor slipped 3.76% after cutting its annual sales target, and Hanwha Aerospace slumped 12.24% on a weak earnings print tied to delayed K9 deliveries to Poland.

Reuters put the KOSPI's October decline at more than 17% and said Japan's Nikkei fell about 3% on the same AI-spend scare, while China's CSI300 headed for its largest monthly drop in a decade.

Program-trading sidecars are rare enough that their appearance itself becomes a sentiment signal. Local leverage and futures-linked selling can turn a Wall Street after-hours move into a full Seoul session rout within hours.

Chip exporters in Korea transmit U.S. hyperscaler fear faster than almost any other equity market. When Alphabet, Amazon and Intel all flash cash-flow or guide warnings in the same 24 hours, Seoul does not wait for a local catalyst.

Why it matters

The KOSPI AI selloff matters because Korea is where the AI hardware trade is most concentrated outside the United States. After the earlier Asian stocks chip selloff and Goldman's KOSPI target cut, Friday's sidecar shows local leverage and program flows can turn a U.S. earnings scare into a full-session rout.

Memory names are especially exposed if data-center demand slows even as hyperscaler capex stays high.

Korea's market-cap concentration in memory and autos means global AI and export scares hit the index harder than they hit broader Asia benchmarks.

What's next

Whether Samsung and SK hynix stabilize into the U.S. open will set the tone for next week's Asia tape. Yonhap's morning market report has the session detail. The KOSPI AI selloff is the clearest Asia echo of this week's Big Tech cash-flow scare.

Stabilization in Samsung and SK hynix into the U.S. cash open is the first tell for whether Friday was a flush or the start of another down week.

Foreign investors have been active sellers in Seoul on AI multiple compression before. When the sidecar triggers, that selling can become mechanical, which is why a single Wall Street after-hours session can dictate Korea's entire morning.

A five-minute sidecar does not stop the session, but it broadcasts that futures-led selling has reached an official stress threshold.