Yen faces vulnerability as Japan’s holiday thins trading liquidity
The Bank of Japan's rate hike to a 31-year high wasn't hawkish enough for markets, and Silver Week's thin volumes could make things worse
The Bank of Japan just delivered its biggest policy shift in decades, and the yen still managed to lose ground. The central bank raised its benchmark interest rate by 25 basis points to 1.25% on September 18, the highest level since 1995, and the currency responded by sliding toward ¥158 per dollar.
The decision passed by a 7-2 vote, with board members Toichiro Asada and Ayano Sato dissenting. The core issue is one of expectations management. The yen had been strengthening in the weeks prior to the meeting on anticipation that the BOJ would use the opportunity to telegraph faster policy normalization. Instead, Governor Kazuo Ueda’s team delivered the rate increase without the accompanying rhetoric that would have convinced markets the tightening cycle had genuine momentum behind it.
Silver Week and the liquidity vacuum
Timing makes this situation considerably more precarious. Japan’s Silver Week holiday begins shortly after the BOJ meeting, pulling Tokyo traders away from their desks and draining liquidity from yen-denominated markets at precisely the wrong moment.
Japan has recent, painful experience with exactly this dynamic. During the Golden Week holiday in April-May 2026, the Ministry of Finance conducted record-scale interventions totaling roughly ¥11.7 trillion, approximately $73 billion, to prop up the yen. Total spending over the surrounding month reached $96.4 billion equivalent.
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Carry trades and intervention calculus
Even at 1.25%, Japan’s benchmark rate remains well below those of most major economies. That gap continues to make the yen an attractive funding currency for carry trades, where investors borrow in low-yielding currencies and park the proceeds in higher-yielding ones. The BOJ’s failure to signal faster rate increases effectively told carry traders that the interest rate differential isn’t narrowing as quickly as feared.
The ¥158 level is already uncomfortable territory, and a move toward ¥160 during holiday-thinned trading could force the ministry’s hand.