The yen fell to its weakest level against the US dollar since 1986, raising the prospect of renewed intervention from Japanese authorities.

The currency slid as investors turned to the dollar on expectations that the US Federal Reserve could raise interest rates this year; Japan faces other structural pressures like a persistent trade deficits and reliance on imported energy.

The currency’s weakness is boosting Japanese exporters’ profits and lifting the stock market, but it also raises import costs and threatens to fuel inflation. “Japan needs to step in again,” a Bloomberg strategist said. “Otherwise, this is a market clearly keen on testing pain points.”