The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September.
Data from the decentralized forecasting platform Polymarket points to a dramatic shift in market participants' expectations regarding Japan's monetary policy. The probability of a key rate hike by the Bank of Japan (BoJ) at the September meeting is estimated by traders at 84%. For comparison, just two weeks ago this figure stood at only 22% — such a sharp reassessment reflects fundamental changes in market dynamics.
The key trigger for revising expectations was the weakening effect of currency interventions by Japanese authorities. The yen, which had previously shown steady gains following coordinated regulator actions, has again come under pressure. This week, the USD/JPY exchange rate rose by approximately 1%, reaching 159.43 — the worst weekly result for the Japanese currency since May of this year.
Failed interventions and a return to fundamental factors
Notably, the yen has already lost about half of the gains it accumulated after the BoJ's joint currency intervention in late July — early August. Before these measures, the exchange rate held around 164 yen per dollar. A similar pattern was observed earlier: after the April intervention, the currency again retreated to its multi-year lows over the following months.
Former chief currency diplomat of Tokyo Mitsuhiro Furusawa emphasizes in his comments that authorities could deploy currency reserves at any moment. However, according to him, officials are also prepared to signal to the market a faster policy tightening to support the national currency. This is an important marker: interventions without changes in interest rates, it seems, are no longer viewed as an effective tool for long-term influence on the exchange rate.
Betting on tightening
The connection between interventions and key rate decisions is becoming increasingly obvious to market participants. Polymarket estimates, exceeding 80% probability of a quarter-point rate hike, reflect a consensus that the BoJ will be forced to move from verbal interventions to real action.
OCBC strategist Sim Moh Siong notes that interventions alone cannot reverse the dynamics of the Japanese currency. "It's no surprise that the yen has given up ground again," he states. In his assessment, the yen needs clear support from the Bank of Japan, which is ready to tighten monetary policy. This view aligns with growing expectations of a faster rate hike, as inflation gradually approaches the target level.
The opposite scenario carries significant risks. If the regulator leaves the rate unchanged, the market will quickly react with disappointment — the yen has already shown a drop to 160 per dollar after similar decisions. Currently, market participants are betting precisely on central bank steps, not on new currency interventions.
My view: The market seems to have finally realized that currency interventions are only a temporary measure, not a solution to a structural problem. Given that inflation in Japan consistently exceeds the 2% target, and a weak yen intensifies imported price pressure, a rate hike in September looks like a logical step. However, one should not rule out a "hawkish surprise" — if the BoJ decides to act more aggressively than expected, this could trigger significant volatility not only in the currency market but also in the cryptocurrency market, given the persistent correlation with global risk appetite.