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Kospi triggers fifth circuit breaker of 2026 as tech sell-off reverses Thursday's record

Samsung and SK Hynix fell 8-9% on June 26, sending the Korean benchmark down 5.81% and halting trade for 20 minutes, while Tokyo's Nikkei surged 4.6% on the same chip data

AI·Money· worsening What Broke·Whose Money ·12 takes · ·rbtfl upd Jun 27, 2026
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developments

  1. KOSPI climbed 5.42% to close at 8,930 on Friday (June 26 local afternoon / June 27 UTC), extending the V-shaped recovery on semiconductor stock rally; Samsung recovered much of its earlier losses. ↗

  2. Samsung announced ~90 trillion won ($58.6B) share buyback; SK Hynix accelerated $26B US ADR offering; KOSPI staged V-shaped recovery, partially reversing the circuit-breaker drop. ↗

The split

The same story, as told by newsrooms in different countries. Their words, attributed and linked.

South Korea

Korea Herald

“The bourse operator issued a circuit breaker for the Kospi on a sharp fall, halting trading for 20 minutes from 12:10 p.m.”

Korean financial pressread the original ↗

South Korea

Seoul Economic Daily

“KOSPI plunges 5.81%, triggers second circuit breaker in three days, with Samsung and SK Hynix pacing the decline.”

Korean business dailyread the original ↗

Japan

Nikkei (Japanese)

“韓国株が急落しサーキットブレーカーが発動する一方、東京市場は半導体株主導で4.6%上昇した。”

Japanese financial press, contrast framingread the original ↗

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Summary

South Korea's Kospi fell 8.19% intraday on June 26 before closing down 5.81% at 8,411.21, the fifth circuit breaker of 2026 and second in three sessions. Samsung fell roughly 9%, Sk Hynix fell 8.36%, erasing 366 trillion won ($246bn) in market value in a single session. The sell-off reversed Wednesday's record high, triggered by US tech sector profit-taking after OpenAI's IPO delay was reported and Apple raised iPhone memory prices to offset rising HBM costs. Tokyo's Nikkei simultaneously rose 4.60% on the same Micron earnings data, with Micron-related Japanese names Kioxia (+13.1%), Advantest (+14.9%) and Tokyo Electron (+8.1%) leading gains.

Why it matters

The Kospi-Nikkei divergence exposes how concentrated Korean equity risk is in two names: Samsung and SK Hynix account for a third of the benchmark, so any AI-capex demand signal swings the index violently. Japan's more diversified exposure to the same semiconductor theme cushions the shock, giving Japanese funds a structural advantage in the memory supercycle.

What to watch

  • Whether the Samsung buyback and SK Hynix ADR offering hold as a floor for KOSPI in subsequent sessions.
  • Blue House briefing on June 30 where Samsung and SK Hynix are expected to present their combined $646B investment plan, which could reinforce or further swing sentiment.
  • Whether the Bank of Korea responds with emergency liquidity measures if the sell-off resumes.

The briefing, by email