BOJ Hikes to 31-Year High, but the Yen Still Weakens. Why?
A paradoxical reaction reveals deeper structural forces at play in global FX markets
Photo by Andrew Dawes on Unsplash
The Bank of Japan raised rates to 1.25%, the highest since 1995, yet the yen weakened. For Treasury Secretary Bessent, it adds another layer to the strong…
The Hike That Didn't Land
The Bank of Japan delivered what markets expected: a 25 basis point hike that brought the policy rate to 1.25%, the highest level since 1995. The decision was split 7-2, with dissenters Toichiro Asada and Ayano Sato, both reflationists appointed by Prime Minister Sanae Takaichi earlier this year, voting to hold. The BOJ cited upside risks to inflation as justification for the move.
And yet the yen weakened 0.45% immediately after the announcement, trading at 156.64 against the dollar. Japanese government bond yields actually fell, with the 10-year dropping 4.9 basis points to 2.947%. For a rate hike intended partly to stem yen weakness, this is a counterintuitive outcome.
The dissenters had a point. Core inflation for August came in at 1.7%, down from 1.8% in July, suggesting price pressures are softening rather than accelerating. Asada argued that with core inflation below the 2% target, the economic situation may not be as robust as the headline rate suggests. This ambiguity gave markets an excuse to sell the news.
The Carry Trade Persists
The yen's continued weakness despite rate hikes speaks to a structural issue that has persisted for the better part of two years. Even at 1.25%, Japanese rates remain far below those in the United States. The rate differential still favors dollar holdings, which keeps the yen carry trade alive. Borrowing in yen to fund higher-yielding dollar assets remains profitable.
This dynamic echoes August 2024, when a surprise BOJ rate hike initially triggered a violent unwind in carry trades, sending equity volatility spiking globally. The difference now is that markets have priced in gradual BOJ tightening, so the shock factor is muted. What remains is the underlying math: until Japanese rates get meaningfully closer to U.S. rates, or until the Fed cuts aggressively, the yen lacks fundamental support.
BOJ board member Hajime Takata described 2026 as a "regime change" in policy, with the central bank no longer tied to a fixed pace of hikes but adjusting to conditions. That flexibility cuts both ways. Markets interpret it as the BOJ reserving the right to pause, which undermines forward guidance and keeps speculative positioning tilted against the yen.
The Bessent Problem
For U.S. Treasury Secretary Scott Bessent, the yen's weakness lands in a difficult spot. Bessent met with Governor Kazuo Ueda on the sidelines of the G20 finance ministers' meeting earlier this month, and the two sides reportedly agreed to a coordinated currency intervention to prop up the yen. That intervention has already occurred, yet the yen continues to drift lower.
The strong dollar creates multiple headaches for U.S. policy. American exporters face competitive disadvantages. Multinational earnings get compressed when translated back to dollars. And perhaps most critically, it amplifies trade tensions at a moment when the administration has leaned into protectionist rhetoric. A weak yen makes Japanese exports cheaper in dollar terms, exactly the dynamic that tariff policy is meant to address through blunter instruments.
Bessent's predecessors have faced similar coordination challenges. Treasury Secretaries going back to the Plaza Accord in 1985 have discovered that sustained currency moves require either massive intervention reserves or genuine convergence in monetary policy. Tokyo and Washington seem to have the former but not the latter.
Historical Parallels and Divergence
The current setup rhymes with several historical episodes, though none are perfect analogs. The 1995 intervention that eventually arrested the yen's slide to 80 per dollar worked because it coincided with genuine shifts in relative economic performance. Japan's economy was entering its lost decade; U.S. growth was accelerating. The fundamental story supported the intervention.
Today, the fundamentals are messier. Japan's economy isn't collapsing, but it's not accelerating either. The U.S. economy has remained more resilient than most forecasters expected through 2025 and into 2026, but cracks are appearing in employment and consumer spending. Neither economy presents a clear outperformance narrative.
The 2022-2023 yen weakness episode is more instructive. Then, as now, the BOJ hiked while the Fed held firm or eased only modestly. The yen hit its weakest level against the dollar since 1986 in July 2024, reaching 161.96. Japanese authorities spent over 15 trillion yen ($97 billion) on intervention throughout 2024. The currency eventually stabilized, but more because global carry trade positions unwound than because intervention forced the issue.
What Credit Spreads and Flows Tell Us
Currency markets are notoriously difficult to trade directionally, but cross-asset signals can provide context. Japanese investors have been steady sellers of foreign bonds in recent months, repatriating capital as domestic yields rise. In theory, this should support the yen. That it hasn't suggests either that foreign inflows into Japanese equities are offsetting the bond flows, or that speculative positioning remains heavily short yen.
Credit spreads, meanwhile, aren't flashing alarm on either side of the Pacific. Investment grade spreads in both markets have remained tight, suggesting no imminent stress. This matters because a genuine risk-off event would likely see the yen strengthen as a traditional safe haven. The lack of that bid confirms this is a rates story, not a risk story.
For U.S. multinationals with significant Japan exposure, or for investors considering Japanese equity allocations, the currency remains the key variable. Japanese equities have performed well in local currency terms, but dollar-based returns have been muted or negative due to yen weakness. That pattern seems likely to persist until the rate differential compresses.
What Changes the Setup
The near-term path depends heavily on what the Federal Reserve does in coming weeks. If the Fed signals a more aggressive cutting cycle, the rate differential narrows and the yen finds support. If the Fed remains cautious, citing persistent inflation or labor market resilience, the dollar's yield advantage persists.
Watch the two-year Treasury yield as a real-time barometer. It moved ahead of equities in recognizing the Fed's 2022-2023 hiking cycle, and it will likely lead again on the downside. Currently sitting around 4.66%, a sustained break below 4.25% would signal the market believes the Fed is done and cuts are imminent. That's the level that would compress the differential enough to matter for yen positioning.
The BOJ's next move likely comes in December, unless inflation surprises to the upside. Between now and then, the yen will trade largely as a function of U.S. data and Fed expectations. For Bessent, that means the strong dollar problem is really a Fed problem, one he can't solve through bilateral negotiations alone.
For informational purposes only. Not investment advice. Published Friday, September 18, 2026.