Korea Stock Market (KRX) Today (August 18): South Korea’s stock market reversed sharply after the benchmark KOSPI opened with a gain of more than 2%. Strong buying in semiconductor stocks initially pushed the index above 7,200, but profit-taking by domestic investors later erased the advance and pulled the KOSPI below the 7,000 mark.
The KOSDAQ also turned lower, while Samsung Electronics slipped into negative territory. In contrast, SK Hynix emerged as a major outperformer, gaining more than 8% as investors continued to bet on strong demand for AI-related memory chips.
Korea Stock Market (KRX) Today (August 18): Why is the Korean Stock Market Down Today?
The Korean stock market lost its early momentum as investors moved to lock in profits after the recent rally. The KOSPI opened at 7,127.77, up 2.15%, and climbed as high as 7,216.62 before selling pressure pushed the index below 7,000.
Foreign investors provided some support through buying, particularly in technology shares, but domestic institutions and retail investors sold stocks heavily. The KOSDAQ followed a similar pattern, opening slightly higher before slipping into negative territory.
Korea Stock Market (KRX) Today (August 18): KOSPI Down By 0.40%
The benchmark KOSPI Composite Index erased its early gains and moved into negative territory during Tuesday’s session. The index opened at 7,127.77, representing a 2.15% increase from the previous close. It then climbed to an intraday high of 7,216.62 before reversing sharply.
KOSPI Performance
- Current Value: 6,950.22
- Daily Change: -0.40%
- Opening Value: 7,127.77
- Intraday High: 7,216.62
- Intraday Low: 6,866.40
- Previous Close: 6,977.94
Korea Stock Market (KRX) Today (August 18): KOSDAQ Down By 0.73%
The technology-heavy KOSDAQ also surrendered its early gains and moved lower during the session.
The index opened slightly higher but failed to maintain the momentum seen in the main KOSPI market. Selling pressure from investors pushed the junior market into negative territory.
KOSDAQ Performance
- Current Value: 858.31
- Daily Change: -0.73%
- Opening Value: 866.59
- Opening Change: +0.22%
Korea Stock Market (KRX) Today (August 18): Samsung Electronics Falls 0.55%
Samsung Electronics initially joined the semiconductor rally, opening sharply higher and reaching an intraday high of ₩288,000. However, the stock later reversed as investors booked profits.
The stock fell to an intraday low of ₩268,000 as the broader KOSPI lost its early momentum.
Samsung Electronics Performance
- Daily Change: -0.55%
- Intraday High: ₩288,000
- Intraday Low: ₩268,000
- Opening: Strongly higher before reversing
Korea Stock Market (KRX) Today (August 18): SK Hynix Up By 8.15%
SK Hynix was the standout among the major Korean technology stocks on Tuesday.
The shares climbed 8.15% to ₩1,779,000, sharply outperforming both the KOSPI and KOSDAQ. The rally reflected continued optimism surrounding the company’s position in the high-bandwidth memory market and the broader AI infrastructure boom.
SK Hynix Performance
- Current Price: ₩1,779,000
- Daily Change: +8.15%
- Market Trend: Strongly higher
- Key Driver: Renewed optimism around AI and HBM demand
Korea Stock Market (KRX) Today (August 18) Performance
- KOSPI: 6,950.22, down 0.40%
- KOSDAQ: 858.31, down 0.73%
- Samsung Electronics: down 0.55%
- SK Hynix: up 8.15%
- KOSPI opening: 7,127.77, up 2.15%
- KOSPI intraday high: 7,216.62
- KOSPI intraday low: 6,866.40
- The KOSPI erased an early gain of more than 2% and moved below 7,000.
- Semiconductor stocks remained at the centre of trading activity.
- Domestic institutions and retail investors increased profit-taking, while foreign investors provided some buying support.
Korea Stock Market (KRX) Today (August 18): Top Gainers
- SK Hynix: +8.15% to ₩1,779,000 — the standout performer among major Korean semiconductor stocks, supported by strong AI-memory demand expectations.
- SK Square: +7.4% — one of the notable gainers as strength in the SK group and technology shares supported the market.
- LS Electric: +5.1% — gained amid continued investor interest in companies linked to power and infrastructure demand.
- SK Inc.: +4.8% — advanced alongside broader strength across SK Group-linked shares.
- Samsung C&T: +3.3% — moved higher during the early market rally
Korea Stock Market (KRX) Today (August 18): Top Losers
- Samsung Electronics: -0.55% after reversing from an early rally and falling to an intraday low of ₩268,000.
- Healthcare stocks: Among the weaker areas on the KOSDAQ as investors booked profits after the recent market rebound.
- Pharmaceutical stocks: Declined during the session, contributing to the KOSDAQ’s 0.73% fall.
- Entertainment & culture stocks: Also moved lower amid the broader profit-taking across growth-oriented shares.
- KOSDAQ growth stocks: Came under pressure as domestic investors locked in gains following the recent sharp recovery.
Korea Stock Market (KRX) Today (August 18): What Should Investors Know?
The biggest takeaway from Tuesday’s session is the sharp reversal in investor sentiment. The KOSPI started the day with a powerful rally and briefly crossed 7,200, but domestic selling quickly erased the gains.
The market’s recent rebound remains closely tied to semiconductor and AI optimism. The KOSPI had recovered strongly from its late-July lows, while Samsung Electronics and SK Hynix regained ground as investors returned to AI-related memory stocks.
However, Tuesday’s reversal shows that investors remain willing to lock in profits after the recent rally. The contrasting performances of Samsung and SK Hynix also highlight the stock-specific nature of the current market.
