South Korea’s KOSPI plunged more than 6% in early trading on the 19th, falling to the 6,400 level. Investor sentiment froze abruptly as surging U.S. long-term Treasury yields, rising oil prices driven by escalating Middle East tensions, and a sharp selloff in U.S. semiconductor stocks converged. A sell-side circuit breaker\u2014which temporarily halts program sell orders\u2014was triggered just over five minutes after the market opened.<\/p>\n
\u25b2 Today’s KOSPI crash resulted from two headwinds\u2014a Middle East-driven oil shock and surging U.S. Treasury yields\u2014transmitting directly into KOSPI’s opening prices via the U.S. semiconductor selloff.<\/p>\n
According to the Korea Exchange, as of 9:27 a.m., the KOSPI was down 6.64% from the previous session at 6,413.43. The index opened down 4.96% at 6,528.77 before extending losses, at one point falling to 6,400.81 intraday.<\/p>\n
At 9:06:02 a.m., a sell-side circuit breaker was triggered when the KOSPI 200 futures index fell 65.00 points (6.02%) from the previous session’s close to 1,013.26. The KOSPI market sell-side circuit breaker is activated when KOSPI 200 futures fall 5% or more and the decline persists for one minute. This brought the total number of sidecar activations on the KOSPI this year to 48 (25 sell-side, 23 buy-side).<\/p>\n
According to Seoul Economic Daily, this year’s sidecar count has already far surpassed the 26 activations recorded during the 2008 global financial crisis. Compared with just three sidecar activations throughout all of 2025, the figure underscores how extraordinary this year’s market volatility has been.<\/p>\n
PeriodActivationsNotes2008 (Global Financial Crisis)26Annual total20253Annual total2026 Jan 2\u2013Jul 2441Buy 20 \u00b7 Sell 212026 Jan 2\u2013Aug 19 (as of today)48Buy 23 \u00b7 Sell 25<\/p>\n
The two largest stocks by market capitalization suffered particularly steep declines. Samsung Electronics traded down more than 7% in the 248,000 won (approximately $180) range, while SK Hynix plunged over 9% to the low 1.5 million won (approximately $1,100) range. SK Square plummeted more than 12%, and Samsung Electronics preferred shares and Hyundai Motor also fell 6\u20137%.<\/p>\n
On the supply-demand front, foreign and institutional investors sold off in tandem, leading the index decline. As of 9:46 a.m., foreigners net sold 1.23 trillion won (approximately $880.1 million) and institutions net sold 578.7 billion won (approximately $413.4 million) on the KOSPI market. Retail investors net bought 1.75 trillion won (approximately $1.3 billion), stepping in to buy the dip, but it was insufficient to defend against the index decline.<\/p>\n
Overnight on Wall Street, all three major indices fell as Middle East instability deepened following the collapse of U.S.-Iran ceasefire negotiations. The Dow Jones Industrial Average fell 0.22%, the S&P 500 dropped 0.69%, and the Nasdaq Composite declined 1.33%. The Philadelphia Semiconductor Index plunged 4.98%, and SK Hynix’s American Depositary Receipts (ADRs) tumbled 9.20%.<\/p>\n
The U.S. 30-year Treasury yield rose to 5.33% intraday, its highest level in 19 years since 2007. The benchmark 10-year Treasury yield also hovered around 4.71%, remaining at its highest level since January 2005. Japan’s 10-year government bond yield also climbed to 2.945% intraday, hitting its highest level in roughly 30 years since 1996.<\/p>\n
International oil prices continued their upward trend. October-delivery Brent crude settled at $91.02 per barrel, while September-delivery West Texas Intermediate (WTI) settled at $84.95 per barrel. Both benchmarks marked their highest levels since the 24th of last month.<\/p>\n
Key indicators related to today’s crash are summarized below.<\/p>\n
CategoryItemFigureNotesStocksSamsung Electronics-7% rangeTrading in 248,000 won rangeStocksSK Hynix-9% rangeLow 1.5 million won rangeStocksSK Square-12% rangeLargest declineStocksSK Hynix ADR (U.S.)-9.20%Based on prior NY sessionBondsU.S. 30-year Treasury yield5.33%Highest in 19 years since 2007BondsU.S. 10-year Treasury yield4.71% rangeHighest since Jan 2005BondsJapan 10-year JGB yield2.945%Highest in ~30 years since 1996OilBrent crude (Oct delivery)$91.02\/barrelHighest since 24th of last monthOilWTI (Sep delivery)$84.95\/barrelHighest since 24th of last month<\/p>\n
U.S. President Donald Trump stated on Truth Social that “there are no ongoing talks or discussions with Iran, and none are scheduled,” adding that the maritime blockade against Iran remains fully in place. Tensions escalated further after a vessel was struck in the Strait of Hormuz. The United Arab Emirates (UAE) announced it had detected two ballistic missiles launched from Iran and subsequently declared it would suspend all trade, commercial, and financial transactions with Iran.<\/p>\n
The KOSDAQ index’s decline was relatively limited compared with the KOSPI. Foreign net buying on the KOSDAQ market partially cushioned the index’s fall. As of 9:46 a.m., the KOSDAQ was down 0.41% from the previous session at 830.79.<\/p>\n
Kiwoom Securities analyst Han Ji-young said, “Market volatility may increase as investors navigate macro uncertainty,” but assessed that “the likelihood of a recurrence of the abnormal supply-demand deterioration and market crash seen in July is low.” Han added, “Since rate-driven market correction pressure has already been partially reflected through yesterday’s sharp decline, the market is likely to show a pattern of recovering intraday losses.”<\/p>\n
Mirae Asset Securities analyst Seo Sang-young noted, “Given that this stems from supply-demand factors rather than deterioration in fundamentals such as HBM order cancellations or memory price declines, the likelihood of consecutive sharp declines is not high.”<\/p>\n
The previous day, the KOSPI closed down 1.55% at 6,869.83, snapping a five-session winning streak. The index had recovered the 7,000 level intraday, rising to 7,216.62 at one point, but gave back all gains amid U.S.-Iran tensions and surging Treasury yields. With today’s plunge, the KOSPI has now declined for two consecutive sessions.<\/p>\n
Market participants view a potential breach of 5% in the U.S. 10-year Treasury yield as a danger signal that could halt artificial intelligence (AI) investment and trigger a bubble collapse. During the global financial crisis, the U.S. 10-year Treasury yield stood at 5.3%. Rising Treasury yields are interpreted as a signal of mounting concerns over inflation and increased government bond issuance driven by expansionary fiscal policies across major economies.<\/p>\n
In Seoul’s foreign exchange market, the won-dollar exchange rate traded at 1,408.5 won, down 5.00 won.<\/p>\n","protected":false},"excerpt":{"rendered":"South Korea’s KOSPI plunged more than 6% in early trading on the 19th, falling to the 6,400 level.…\n","protected":false},"author":2,"featured_media":124333,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[45261,48901,114,337,336,335,8909,276,241,275,64336,3392],"class_list":["post-124332","post","type-post","status-publish","format-standard","has-post-thumbnail","category-sk-hynix","tag-brent-crude","tag-han-ji-young","tag-iran","tag-korea-exchange","tag-kosdaq","tag-kospi","tag-philadelphia-semiconductor-index","tag-samsung-electronics","tag-sk","tag-sk-hynix","tag-u-s-10-year-treasury-yield","tag-wti"],"_links":{"self":[{"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/posts\/124332","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/comments?post=124332"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/posts\/124332\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/media\/124333"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/media?parent=124332"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/categories?post=124332"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/korea\/wp-json\/wp\/v2\/tags?post=124332"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}