Dollar Soars as Yen Tumbles to 40-Year Low

The US dollar is poised for its biggest weekly gain since mid-June due to rising oil prices and increasing expectations of interest rate hikes by the Federal Reserve. The yen, on the other hand, has experienced its largest weekly percentage decline in more than two months, falling to a 40-year low.

Japan's Finance Minister Satsuki Katayama reiterated the government's readiness to take action in the foreign exchange market, but analysts believe another intervention by Japanese officials would have only a short-lived effect without coordinated steps from the Bank of Japan (BOJ) such as more aggressive rate hikes.

The U.S. Treasury Department has also called for rate hikes by the BOJ, warning that excessive currency volatility is undesirable. The dollar index rose 0.01% to 101.46 and was up about 0.7% for the week, with the greenback gaining nearly 0.9% against the yen.