The South Korean won weakened to around 1,353 per dollar as markets priced a roughly 92% chance of a 25-basis-point Federal Reserve rate increase this week. Treasury yields remained near 5%, while crude oil stayed above $100 a barrel amid Middle East tensions, raising concern over South Korea's energy-import costs. Foreign investors sold a net 3.2 trillion won of local stocks, adding pressure on the currency, though continued dollar sales by semiconductor exporters helped curb losses. The move followed earlier trading around 1,348 and an offshore test of 1,350, underscoring persistent sensitivity to U.S. monetary policy, bond yields and oil supply risks.