During Korea’s regular trading session (09:00–15:30) on August 20, 2026, the KOSPI rose 381.41 points (5.89%) from the previous trading day to 6,852.58 points, while the KOSDAQ gained 16.43 points (1.99%) to 840.89 points. Among the tracked stocks, SK hynix posted the largest gain, rising 12.73%, while Hyundai Motor’s 0.85% gain showed a different relative pattern from the indexes.

KOSPI Returns to 6,852.58 Points in a Broader Rebound Than the KOSDAQ

Index August 20, 2026 Regular-Session Close Change From Previous Trading Day
KOSPI 6,852.58 points +381.41 points (+5.89%)
KOSDAQ 840.89 points +16.43 points (+1.99%)

The KOSPI opened at 6,680.34 points during the regular session on August 20, 2026, rose as high as 6,904.55 points, recorded an intraday low of 6,600.09 points, and closed at 6,852.58 points. KOSPI closing data

The KOSDAQ opened at 843.99 points on August 20, 2026, reached a high of 850.77 points and a low of 834.69 points, then finished the regular session at 840.89 points. KOSDAQ closing data

The editorial interpretation of the closing data is clear. Both indexes rose on August 20, 2026, but the KOSPI’s 5.89% gain exceeded the KOSDAQ’s 1.99% gain. However, the relationship among the open, high, low, and close shows that day’s price range and does not establish a causal link showing that specific news or investor groups produced the index gains.

SK hynix and SK Square Outperform the Index Gain

SK hynix closed at 1,691,000 won on August 20, 2026, up 191,000 won (12.73%) from the previous trading day. It opened at 1,598,000 won, reached a high of 1,721,000 won and a low of 1,576,000 won, with regular-session volume of 8,722,217 shares. Its 12.73% gain on August 20, 2026, exceeded both the KOSPI’s 5.89% gain and the KOSDAQ’s 1.99% gain. SK hynix closing data Previous analysis is available at the SK hynix stock hub.

SK Square finished the regular session at 1,123,000 won on August 20, 2026, up 119,000 won (11.85%). On the same trading day, it recorded an open of 1,076,000 won, a high of 1,131,000 won, a low of 1,029,000 won, and regular-session volume of 1,291,896 shares. SK Square closing data Previous records are available at the SK Square stock hub.

Samsung Electronics closed at 271,000 won on August 20, 2026, up 23,500 won (9.49%) from the previous trading day. It opened at 258,000 won, reached a high of 274,000 won and a low of 252,000 won, with regular-session volume of 42,320,704 shares. Samsung Electronics closing data Historical analysis for the individual stock is available at the Samsung Electronics stock hub.

The editorial interpretation is that the gains of SK hynix, SK Square, and Samsung Electronics exceeded the KOSPI’s gain on August 20, 2026, with these three stocks leading strength among the tracked stocks. However, relative performance alone does not establish that semiconductor-sector or holding-company-related factors were the direct cause of the index rebound.

Hyundai Motor Rises 0.85% From the Previous Trading Day, Relatively Limited Among Tracked Stocks

Hyundai Motor closed at 417,500 won on August 20, 2026, up 3,500 won (0.85%) from the previous trading day. On the same trading day, it opened at 419,000 won, reached a high of 425,000 won and a low of 408,000 won, with regular-session volume of 731,444 shares. Hyundai Motor closing data Previous analysis is also available at the Hyundai Motor stock hub.

Hyundai Motor’s 0.85% gain on August 20, 2026, was lower than the KOSPI’s 5.89% gain and the KOSDAQ’s 1.99% gain. Its closing price was also 1,500 won lower than its August 20, 2026 opening price of 419,000 won. This is a closing-data-based comparison showing that Hyundai Motor’s relative gain was limited among the tracked stocks that day; it is not a causal assessment of company-specific factors or sector trading flows.

Read Investor Flow Direction and Pre-Market Reports Separately

Investor flow data for August 20, 2026, shows net selling of 22,714 hundred million won by individual investors, net buying of 17,079 hundred million won by foreign investors, and net selling of 4,904 hundred million won by institutions. Investor flow data for August 20, 2026 Foreign net buying and the KOSPI’s rise, as well as individual and institutional net selling and the index’s rise, occurred on the same trading day, but this concurrence alone cannot establish that the trading of any one investor group directly produced the index movement.

A collected pre-market Yonhap News report presented positive developments from the United States and SK hynix’s shareholder returns in its headline as the backdrop for the KOSPI’s attempted rebound. This was the market interpretation presented by that report and cannot be verified from regular-session closing data alone on August 20, 2026, or confirmed as the cause of that day’s gain. Original Yonhap News article

Another collected article cited the Korea Development Institute’s (KDI) upward revision to its growth forecast and a semiconductor supercycle as pre-market observation factors. This, too, should be distinguished as the interpretation of the original article. The facts confirmed in this briefing are the closing results that semiconductor-related tracked stocks SK hynix rose 12.73% and Samsung Electronics rose 9.49% on August 20, 2026. Original pre-market news article

Three Items to Check in the Next Regular Session

  • For the next regular-session close, the KOSPI should be checked against its August 20, 2026 close of 6,852.58 points and that day’s high of 6,904.55 points, while the KOSDAQ should be checked against its close of 840.89 points and that day’s high of 850.77 points.

  • It is necessary to observe how the relative moves of SK hynix at 12.73%, SK Square at 11.85%, Samsung Electronics at 9.49%, and Hyundai Motor at 0.85% on August 20, 2026, change in the next regular session. These are observation benchmarks only and do not provide grounds for determining the direction of the next trading day.

  • It is necessary to check whether the investor flow direction of individual net selling of 22,714 hundred million won, foreign net buying of 17,079 hundred million won, and institutional net selling of 4,904 hundred million won on August 20, 2026, continues in the next regular-session data. Investor flows and prices should be observed together, but a single trading day’s figures cannot establish a causal relationship.