The U.S. joined a global rate-hike cycle on September 16, raising its benchmark interest rate for the first time in three years and two months as international oil prices exceeded $100 a barrel amid the Iran war. The European Central Bank (ECB) had already raised its benchmark rate by 0.25 percentage points to 2.5% annually on September 10, while the Bank of Japan (BOJ) was expected to lift its rate from 1.0% to 1.25% on September 18, the highest level in 31 years. The Bank of Korea moved ahead of the U.S., raising its benchmark rate by 0.25 percentage points in both July and August to 3.0% annually, but renewed U.S. tightening has widened the interest-rate gap and increased pressure on the won, inflation and domestic borrowing costs. South Korea's won-dollar exchange rate closed at 1,382.2 won on September 17, while the KOSPI slipped 0.04%. Domestic three-year government bond yields have risen from about 3.8% annually in early July to around 4% this month, and fixed-rate mortgage rates at the five major banks have climbed from the high 3% range at the end of last year to about 5% at the lower end, with the upper end recently exceeding 7%. Authorities agreed to monitor further U.S. rate hikes, oil prices and global capital flows closely.