In South Korea’s regular trading session on August 6, 2026, the KOSPI plunged 4.58% to 6,296.38 points, while the KOSDAQ rose 0.26% to 801.67 points. All tracked stocks declined, with SK Square and SK hynix falling 13.32% and 10.37%, respectively, substantially more than the KOSPI. Retail investors recorded net purchases of KRW 33,388 hundred million on August 6, 2026, while foreign and institutional investors posted net sales of KRW 33,273 hundred million and KRW 1,214 hundred million, respectively.

KOSPI Plunges 301.88 Points, While KOSDAQ Closes Higher

Index August 6, 2026 Close August 6, 2026 Change
KOSPI 6,296.38 points -301.88 points (-4.58%)
KOSDAQ 801.67 points +2.08 points (+0.26%)

The KOSPI closed the regular session on August 6, 2026, at 6,296.38 points, down 301.88 points, or 4.58%, from the previous trading day. During the same session, it opened at 6,478.75 points, reached a high of 6,550.94 points, and fell to a low of 6,238.32 points. The close was 182.37 points below the open and 58.06 points above the low. The range between the regular-session high and low on August 6, 2026, was 312.62 points. KOSPI closing data

The KOSDAQ closed the regular session on August 6, 2026, at 801.67 points, up 2.08 points, or 0.26%, from the previous trading day. It opened at 797.44 points, reached a high of 813.54 points, and fell to a low of 779.08 points. The close was 4.23 points above the open and 11.87 points below the high. The range between the high and low during the same session was 34.46 points. KOSDAQ closing data

The difference between the two indexes’ percentage changes on August 6, 2026, was 4.84 percentage points. The KOSPI’s sharp decline below its opening level, alongside the KOSDAQ’s higher close above its opening level, shows divergence within the market. However, the indexes’ contrasting moves alone do not establish that sectors or investor groups caused the difference.

SK Square and SK hynix Post Double-Digit Declines

SK Square closed the regular session on August 6, 2026, at KRW 970,000, down KRW 149,000, or 13.32%, from the previous trading day. It posted the largest decline among the tracked stocks, falling 8.74 percentage points more than the KOSPI’s 4.58% decline during the same session. Both the open and high were KRW 1,090,000, while the low was KRW 968,000 and trading volume was 1,089,748 shares. The close was KRW 120,000 below the open and KRW 2,000 above the low. SK Square closing data Previous coverage is available through the SK Square stock hub.

SK hynix closed the regular session on August 6, 2026, at KRW 1,495,000, down KRW 173,000, or 10.37%, from the previous trading day. Both the open and low were KRW 1,168,000, while the high was KRW 1,614,000 and trading volume was 7,913,833 shares. The close was KRW 327,000 above the open but KRW 119,000 below the high. The difference between the high and low during the same session was KRW 446,000. The price path combined a double-digit decline from the previous close with a rebound from the intraday low. SK hynix closing data Related coverage is compiled in the SK hynix stock hub.

Both stocks fell substantially more than the KOSPI on August 6, 2026, but their intraday movements differed. SK Square closed only KRW 2,000 above its low for the session, while SK hynix closed KRW 327,000 above its low. This reflects a verifiable difference in their price paths and does not indicate shared company-specific developments or an identical cause for the selling.

Samsung Electronics Also Underperforms the Index, While Hyundai Motor’s Decline Is Limited

Samsung Electronics closed the regular session on August 6, 2026, at KRW 230,500, down KRW 15,500, or 6.30%, from the previous trading day. It opened at KRW 241,500, reached a high of KRW 246,000, and fell to a low of KRW 228,000, with trading volume of 38,711,244 shares. The close was KRW 11,000 below the open and KRW 2,500 above the low. The stock fell 1.72 percentage points more than the KOSPI during the same session but declined 4.07 percentage points less than SK hynix. Samsung Electronics closing data The stock’s historical performance is available through the Samsung Electronics stock hub.

Hyundai Motor closed the regular session on August 6, 2026, at KRW 400,000, down KRW 4,500, or 1.11%, from the previous trading day. It opened at KRW 403,500, reached a high of KRW 415,000, and fell to a low of KRW 390,000, with trading volume of 835,753 shares. The close was KRW 3,500 below the open but KRW 10,000 above the low. Although the stock moved in the same downward direction as the KOSPI and the other tracked stocks, its decline was 3.47 percentage points smaller than the KOSPI’s during the same session. Hyundai Motor closing data Previous coverage is available through the Hyundai Motor stock hub.

The editorial interpretation based on closing data is that the weakness on August 6, 2026, was not evenly distributed among the tracked stocks. SK Square and SK hynix posted double-digit percentage declines, and Samsung Electronics also underperformed the KOSPI, while Hyundai Motor’s decline was more limited than the index’s. This comparison classifies each company’s percentage move and does not explain the causes of the differences.

Final Investor Flows Must Be Distinguished From Intraday Reports

Investor-flow data for August 6, 2026, showed net purchases of KRW 33,388 hundred million by retail investors. Foreign investors recorded net sales of KRW 33,273 hundred million during the same session, while institutional investors posted net sales of KRW 1,214 hundred million. Foreign and institutional net selling occurred during the same regular session as the KOSPI’s decline, but the simultaneous moves alone do not establish that selling by those two investor groups caused the index’s decline. Investor flow data

A Yonhap News Agency report published before the market opened on August 6, 2026, cited the possibility that the South Korean market could “pause for breath” amid mixed US stock-market performance as part of the day’s backdrop. This was a forecast and interpretation presented in a premarket article, not evidence that conclusively explains the KOSPI’s subsequent 4.58% closing decline. Original Yonhap News Agency market-view report

An intraday Yonhap News TV report on August 6, 2026, said that foreign investors were net sellers while retail and institutional investors were net buyers as the KOSPI declined. However, the final regular-session data showed institutional net sales of KRW 1,214 hundred million on August 6, 2026. Intraday and final investor-flow figures reflect different reporting times and should not be combined when interpreting the regular session’s closing results. Original Yonhap News TV intraday report

A separate premarket report on August 6, 2026, cited expectations that the Strait of Hormuz would reopen, strong earnings from major companies, and gains in US semiconductor stocks as the backdrop before the open. This was also the report’s interpretation of overseas markets and premarket sentiment. Those factors alone cannot explain why Samsung Electronics and SK hynix fell 6.30% and 10.37%, respectively, by the close of South Korea’s regular session. Original premarket review article

Three Items to Monitor in the Next Regular Session

  • Monitor how the KOSPI changes the 58.06-point gap between its August 6, 2026 close of 6,296.38 points and low of 6,238.32 points in subsequent regular-session closes. For the KOSDAQ, its August 6, 2026 close of 801.67 points and open of 797.44 points can serve as comparison benchmarks.

  • Compare SK Square’s and SK hynix’s August 6, 2026 declines of 13.32% and 10.37% with Samsung Electronics’ 6.30% decline and Hyundai Motor’s 1.11% decline in subsequent regular sessions. This is a benchmark for retrospective price comparisons, not a directional prediction or trading judgment.

  • Monitor whether the August 6, 2026 directions of retail net purchases of KRW 33,388 hundred million, foreign net sales of KRW 33,273 hundred million, and institutional net sales of KRW 1,214 hundred million are maintained in subsequent final regular-session data. Even if investor flows and closing prices move in the same direction, that fact alone does not establish causation.