Yen Rally Toward 155 Looks Fundamental as Intervention Signs Fade

The 155 area has been a critical floor this year: it held after intervention-driven yen gains in late April/early May and again in late July/early August. This time, the sharp move is being read differently. The latest Bank of Japan current-account data released a day earlier showed no sign of major intervention to support the yen, increasing the likelihood of a more sustained rebound.

Instead, the stronger yen has been encouraged by building expectations for a faster pace of BoJ policy tightening under pressure from the US. Treasury Secretary Scott Bessent's recent comment that "I have information the market does not have" and reports that he expressed concerns to Finance Minister Katayama over fiscal policy and central bank independence at the G20 meeting have fuelled speculation of a policy shift in Japan. Hawkish comments from BoJ officials including Governor Ueda added to the repricing.

The fundamental read contrasts with the initial reaction from the prior session, when a sharp yen jump was attributed to possible intervention and had a knock-on negative effect on the dollar across the board. Now the current-account evidence points away from that explanation, though the dollar's broad sensitivity to yen swings remains intact.

The yen's move comes during a broader dollar retreat. The US dollar declined 0.4% in August, a second consecutive monthly decline, after the July drop was driven by joint yen-buying intervention by Japan and the US. The Bank of Japan meets on 18 September, and markets are nearly fully priced for a 25 basis point hike, reinforcing the tightening expectations behind the yen's strength.

For asset markets, yen strength toward 155 is treated as a dollar headwind. The implied transmission is broad: it lifts non-US assets, supports US risk appetite via a softer dollar, and pressures exporter earnings. Affected exposures include EWJ, SPY, XLI and XLY, reflecting the cross-asset reach of the currency move.

The durability of the rebound now depends on whether USD/JPY can hold below 155 and whether BoJ communication keeps tightening expectations alive. The September central-bank calendar — with the BoJ meeting nearly fully priced for a hike — makes the next policy signals the critical test, and a confirmed break below the support would mark a shift toward sustained yen strength.