The KOSPI, which had risen to 9,385.59 intraday on June 19, fell to 5,593.56 on July 30, a drop of more than 40% from its peak, as concerns about an artificial intelligence (AI) investment bubble by U.S. hyperscalers spilled over into debate about a semiconductor peak-out. The won-dollar exchange rate, which had surged to the 1,550-won range in early July, fell by more than 120 won in a month to the 1,430-won range, breaking its typical synchronization with KOSPI. The AI investment boom has turned the "exchange rate determination theory based on external interest rate differentials" into a stale tale, as global capital flows reacted more sensitively to expected investment returns than to interest rate gaps. From Jan. 2024 to the first half of 2025, domestic retail investors were net buyers of $28.3 billion (about 33 trillion won) in U.S. stocks, while net sellers of 19.8 trillion won in domestic stocks; during this period, the S&P 500 and Nasdaq rose more than 40%, while KOSPI's gain was limited to 4%. The roughly threefold surge in KOSPI from the 2,900s in June 2025 to the 8,400s this June is seen as a derivative effect of the U.S. AI investment boom, which boosted demand