BOJ’s 1.25% Hike Is the Start of the End for the Yen-Era Trade

Tokyo Is No Longer Waiting for Inflation to Come to It

The Bank of Japan is widely expected to raise its policy rate to 1.25 percent on September 18, marking the third consecutive increase and pushing borrowing costs to their highest level since April 1995. The timing is notable not because of the number itself but because of the pace. Since ending negative rates in March 2024, the BOJ had been moving roughly every six months. This time the gap shrinks to three.

The driver is straightforward: imported inflation. Japan’s trade-weighted yen has been under sustained pressure, and with Middle East tensions keeping crude prices elevated, the cost of bringing energy and raw materials into the country continues to climb. A weaker yen means a more expensive bill at the border, and that bill is now working its way through to shelf prices. The BOJ is no longer watching inflation from the outside—it is feeling it.

Reuters surveyed 68 economists this month. Sixty-six predicted the 1.25 percent outcome. Of those, roughly 62 percent see the policy rate reaching at least 1.75 percent by the second quarter of next year. That is a steep climb for a central bank that spent decades fighting deflation. If the market takes that guidance seriously, the yen is not just stabilising—it is repricing higher on a trajectory that catches most portfolio managers off guard.

The Real Question Is What Ueda Says After the Decision

The rate itself is priced in. What matters is the tone.BOJ Governor Kazuo Ueda’s press conference will set the cadence for everything that follows. Ha Geon-hyeong at Shinhan Investment Research noted that if the BOJ signals an accelerated path, the dollar-yen could snap from the current 155 range toward 150. That is a 3 percent move in a single pair, and it would reverberate through every asset class that depends on yen funding.

Ueda has been careful not to commit to a preset path, which is precisely why markets are listening for cracks in that language. Any shift from “data-dependent gradualism” toward something sharper would be interpreted as a green light for further yen strength—and a red flag for the carry trade.

The Yen-Won Correlation Is a New Risk Factor for Korea

For years, the Korean won tracked the Chinese yuan far more closely than the Japanese yen. That pattern has been shifting. Recent data shows the won and yen moving in the same direction with noticeably higher correlation than in prior cycles. The mechanism is partly mechanical: when the BOJ raises rates and the yen strengthens, capital flowing out of yen-funded positions often rotates into other Asian currencies, lifting the won alongside.

That co-movement cuts both ways for Seoul. On the upside, a stronger yen pulling the won higher can cap further depreciation of the dollar-won rate, which sits around 1,380 won per dollar following US rate moves. A firmly anchored won reduces imported inflation pressure at the customs desk and gives the Bank of Korea more breathing room.

On the downside, a rapidly appreciating yen that drags the won up too fast becomes a headache for Korean exporters. Chaebol firms like Samsung Electronics and Hyundai Motor compete on price in global markets. When the won strengthens, their revenues convert into fewer local currency units, and margin pressure mounts. That is already a live concern for companies that reported earnings in the first half of the year under a weaker won environment.

The Yen Carry Trade Is Unwinding—But Not Like 2024

The carry trade—borrowing cheap yen to fund higher-yielding assets elsewhere—has been the elephant in every Asian portfolio for the past two years. When the BOJ nudged rates up last summer, the unwinding was violent. Global equities sold off, volatility spiked, and emerging market currencies came under fire. Many investors got burned.

Haehan Investment Research argues that this time the shock will be muted because a significant portion of the carry trade was already liquidated during the 2024 episode. The easy exits have happened. What remains is a smaller, more concentrated book of positions that may not move markets as dramatically when forced to unwind.

That assessment is plausible but not reassuring. The remaining carry trade is concentrated in specific pockets—Japanese government bond long-only funds, Asian credit strategies, and certain macro hedge funds. When those players are forced to sell, they do not sell everything at once. They sell into weakness, which creates a feedback loop. A sharp yen move triggered by Ueda’s comments could still produce a disorderly moment even if the total volume of outstanding positions is smaller.

Who Wins, Who Loses, and What Comes Next

The winners from a faster BOJ normalisation are clear in theory and harder to realise in practice. Japanese banks benefit from wider net interest margins. Domestic borrowers feel the pinch, but that is a slow burn. Foreign investors holding yen-denominated assets see currency gains, provided they timed the entry correctly.

For Korea, the impact is asymmetric. Exporters lose competitiveness if the won strengthens too fast. Portfolio investors face currency translation risk on yen-exposed positions. The won’s recent correlation with the yen means that a BOJ-driven shock does not stay contained in Tokyo—it leaks into Seoul almost immediately.

The dollar-yen axis is where the real pivot will show. If Ueda guides markets toward 150, the dollar-yen pair falls while the dollar-won likely rises again, testing the 1,380 level that has become a psychological resistance zone. If he stays cautious, the yen drifts weaker and the carry trade breathes easier for another quarter.

One detail the English-language press often misses: the BOJ’s own wage-setting mechanism is now feeding directly into rate expectations. Spring’s shunto negotiations produced the largest wage settlements in three decades. Those increases are rolling into corporate pricing and household budgets throughout 2026. The BOJ is not creating inflation—it is responding to it. That distinction matters because it means the hiking cycle has structural support, not just cyclical momentum.

What happens next hinges on whether the market believes Ueda can deliver steady increases without spooking an economy that still carries the scars of deflation mindset. If he walks the line, the yen strengthens gradually and Asian markets adjust quietly. If he slips toward hesitation, the yen stalls and carry trades reposition for another round. If he leans too hard, the unwinding accelerates and volatility returns.

The rate to 1.25 percent is not the story. The story is the three-month gap between hikes, the correlation shift between the won and the yen, and the fact that most portfolio managers outside Tokyo still think of Japanese monetary policy as something that happens slowly. It is not happening slowly anymore.