The KOSPI closed at 6,715.41 on September 17, down 0.04%, or 2.56 points, despite opening 0.91% higher at 6,779.02 and briefly gaining 1%. Foreign and institutional selling pressure erased the early advance, with foreign investors recording net sales of 2.4606 trillion Korean won, compared with net purchases of 526.1 billion won by individuals and 229.5 billion won by institutions. The Federal Reserve raised its benchmark rate by 0.25 percentage points to 3.75%–4.00% at the previous night's FOMC (Federal Open Market Committee) meeting, its first increase in three years and two months. Analysts said the move had largely been priced into domestic equities, while stabilizing oil prices supported sentiment. The CME FedWatch Tool projected further increases in January and April 2027, taking the expected terminal rate to 4.25%–4.50%, but the Fed's dot plot reduced uncertainty around the timing and scale of future tightening. WTI crude fell to around $102 a barrel, apparently helped by positive remarks from U.S. President Donald Trump. Seven of the market's 10 largest stocks by market capitalization declined, although Samsung Electronics and SK Hynix posted slight gains. Defense shares rose after Hanwha and a UAE state-owned defense company agreed to collaborate on the UAE's integrated air defense network, while oil refiners advanced on expectations of prolonged Middle East tensions. The KOSDAQ rose 0.76% to 822.18, supported by materials, parts and equipment stocks; institutions were net buyers of 47.1 billion Korean won, while individuals and foreign investors were net sellers.