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South Korean stocks suffered their worst daily drop in months on Friday, May 15, 2026, as the benchmark KOSPI plummeted 6.12% to close at 7,493.18, according to Yonhap News Agency. The index had earlier soared past the historic 8,000-point mark for the first time, touching an intraday high of 8,046.78, before reversing sharply as investors cashed out gains from a record-breaking rally.

The plunge, which saw the index fall as low as 7,371.68, triggered a sell-side sidecar — a circuit breaker mechanism — for the first time since April 2, Yonhap reported. Trading volume was heavy at 878.7 million shares worth 57.8 trillion won (US$38.5 billion), with losers outnumbering winners 704 to 165.

Coverage Comparison

All reporting on the event came from Yonhap News Agency, South Korea's leading wire service, which provided multiple updates throughout the day. Early reports noted the index fell more than 3% late Friday morning, while subsequent updates confirmed the closing decline of over 6%. A separate Yonhap opinion piece offered a critical perspective on the market's rapid ascent, warning of overheating risks.

Key Claims

  • The KOSPI briefly topped the 8,000-point level for the first time in its history, rising as high as 8,046.78, before closing at 7,493.18, down 488.23 points or 6.12%, according to multiple Yonhap reports.
  • Foreign investors dumped 5.6 trillion won worth of local shares, marking the seventh consecutive session of selling, while institutions unloaded 1.7 trillion won. Retail investors purchased 7.2 trillion won, Yonhap reported.
  • Samsung Electronics nosedived 8.61% to close at 270,500 won, while SK hynix slid 7.66% to 1.82 million won, per Yonhap. The drop was attributed to profit-taking after a massive rally and ongoing labor tensions at Samsung.
  • The sell-off was triggered by lingering uncertainties over the Middle East crisis, particularly reports that U.S. President Donald Trump, during his state visit to China, said he would not be "much more patient" with Iran, renewing concerns about the U.S.-Israeli war against Iran and its impact on global oil prices.
  • Lee Kyoung-min, an analyst at Daishin Securities, told Yonhap that the end of the first-quarter earnings season also fueled short-term profit-taking, as expectations for strong earnings appeared to have passed their peak.
  • Yonhap also noted that bond prices closed sharply lower, indicating a broader market shift.

Perspectives

Market Participants

Foreign and institutional investors took profits after a historic rally driven by semiconductor and AI-related stocks, while retail investors bought the dip, purchasing 7.2 trillion won worth of shares. The sharp reversal highlights the volatility of a market that had risen from around 4,300 at the start of the year to briefly touch 8,000.

Geopolitical Factors

Renewed concerns over the Middle East conflict, following President Trump's comments on Iran, were cited as a key catalyst. Yonhap reported that rising oil prices and geopolitical uncertainty prompted investors to reduce risk exposure.

Analyst View

Analysts pointed to profit-taking after a record-breaking rally, with the end of the earnings season removing a key support. Lee Kyoung-min of Daishin Securities noted that expectations for strong earnings had "passed their peak," leading to short-term selling.

Warning on Overheating

A Yonhap opinion piece cautioned that the rally had become "breathtaking," with the market's capitalization surpassing 7,000 trillion won and the Buffett Indicator — market cap-to-GDP ratio — soaring past 200%. It highlighted ballooning margin loans of around 36 trillion won and net short-selling balances of roughly 28 trillion won, warning that the market must not "be reduced to a casino for speculators." However, these figures appeared only in the opinion piece and were not part of the news reports.

Conclusion

The KOSPI's dramatic reversal after breaching the 8,000-point milestone underscores the fragility of a market that had risen steeply on the back of AI optimism. With foreign investors selling for a seventh straight session, retail buyers absorbing the supply, and geopolitical tensions simmering, the coming sessions will likely determine whether this is a temporary correction or the start of a deeper pullback. Yonhap's reporting indicates that market participants will be closely watching developments in the Middle East and the outcome of Samsung's labor dispute.