Japan signals decisive FX steps if speculative currency moves persist

By Kentaro Sugiyama and Makiko Yamazaki

TOKYO, March 30 (Reuters) - Japanese authorities stand ready to take "decisive" steps if speculative moves persist in the foreign exchange market, top currency diplomat Atsushi Mimura said on Monday, delivering the strongest warning yet of possible yen-buying intervention.

Mimura, the vice finance minister for international affairs, was speaking after the yen JPY=EBS softened past 160 to the dollar on Friday to the weakest since July 2024, when Japanese authorities last intervened.

"We are hearing that speculative moves are increasing in the currency market, in addition to the crude futures market. If this situation continues, it may be time to take decisive measures," Mimura told reporters.

It was the first time he used the term "decisive," language traders typically read as a signal of authorities' readiness to intervene.

Finance Minister Satsuki Katayama has used the term in recent weeks, but traders had been watching for Mimura to follow suit, given his typically cautious tone.

Mimura has not used the word publicly since taking office in late July 2024, a few weeks after authorities last intervened to support the yen.