The yen’s weakness has become a growing issue for Japan’s policymakers, given its role in driving up import prices and household living costs. It’s also become a worry for the US.Japanese authorities spent almost US$74 billion in late April to support the currency following two months of steep declines.

The U.S. and Japan are said to have jointly intervened to prop up the Japanese yen for the first time in nearly 30 years after the currency plunged to its...

President Donald Trump said Sunday that the US is supporting the Japanese yen as “a signal of friendship” at a time when the currency has dropped to a 40-year low against the US…