South Korea's KOSPI opened sharply higher on Sept. 22 as global technology stocks and bargain hunting boosted sentiment, briefly reaching 7,171.44 points. The index later surrendered almost all of its roughly 150-point intraday gain as foreign investors and institutions sold into strength, closing at 7,017.91, up 10.19 points, or 0.15%. Retail investors bought a net 156.5 billion won, absorbing net sales of 57.9 billion won from foreigners and 94.7 billion won from institutions. The KOSDAQ fell 0.23% to 834.38, ending a five-session advance. The won strengthened sharply, with the dollar exchange rate falling 22.8 won to 1,358.2 won. Market experts said the reversal highlighted heavy selling pressure near the KOSPI's upper levels and unstable investor positioning, while volatility could remain tied to major economic data and corporate earnings announcements.