Kospi falls 5.2 percent as sell sidecars hit both markets

South Korea's Kospi was down 5.2 percent late in Thursday's session in Seoul after sell sidecars halted program selling on both the Kospi and Kosdaq markets, as the selloff in chip stocks deepened through the afternoon.

Why it matters: The split, chip heavy Seoul, Taipei and Tokyo down while Hong Kong and Shanghai rally, shows a rotation out of AI exposed names rather than a regional risk off move, and Seoul's memory makers remain the region's most exposed stocks to any tightening of US data centre rules after the Democratic midterm sweep.

Data as of Intraday figures as of 10:24 a.m. Korea time on November 5, 2026, from Yonhap News Agency, in Korean, read in full via the live browser in the original run (the direct fetch was blocked, and the browser route is the second route under the blocked-item rule); index and sidecar figures are Korea Exchange data as reported by Yonhap. Update: later session figures are investingLive's Asia-Pacific wrap of November 5, 2026, read in full in this run, which reports index moves in round terms (about 4.8 percent for the Kospi). Afternoon update: figures as of 2:37 p.m. Korea time on November 5, 2026, from MoneyToday and Seoul Economic Daily, both read in full in this completion run, corroborated by Yonhap via K-VIBE for the morning sidecar; intraday, so the closing figures may differ. Developing item.

Latest: The selloff deepened further in the afternoon, with the Kospi down 5.20 percent at 5,388.51 at 2:37 p.m. and the Kosdaq triggering its own sell sidecar at 2:27 p.m., the first time both markets have triggered sell sidecars on the same day since October 15, according to MoneyToday and Seoul Economic Daily. Samsung Electronics was down 7.57 percent and SK hynix down 9.38 percent at 2:37 p.m. Earlier in the session the rest of the region split along the same AI line, with Tokyo’s Nikkei down about 1.5 percent while Hong Kong’s Hang Seng rose about 3 percent, according to investingLive’s Asia-Pacific wrap.

South Korea’s Kospi fell sharply on Thursday morning in Seoul, down 4.73 percent at 5,414.82 at 10:24 a.m. after opening down 1.82 percent at 5,580.09, while the Kosdaq was down 4.57 percent at 682.30. At 10:16 a.m. the Kospi 200 futures index, down 5.21 percent at 843.96, triggered a sell sidecar that suspended program sell orders for five minutes, the first such halt in about a week.

Samsung Electronics was down 6.65 percent and SK Hynix down 8.88 percent at the 10:24 a.m. snapshot, widening losses from the open. Yonhap attributed the fall to growing concern about tighter regulation of AI data centre construction after the Democratic Party’s sweep of the US midterm elections, alongside a fall in the US semiconductor index.

Kospi falls 5.2 percent as sell sidecars hit both markets

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