The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September.
Participants on the decentralized prediction platform Polymarket have sharply shifted their expectations regarding Japan's monetary policy. In just two weeks, the probability of a key interest rate hike by the Bank of Japan (BoJ) at the September meeting has surged from 22% to an impressive 84%. This signals a dramatic shift in market sentiment, which is now confident in the regulator's policy tightening.
The Intervention Effect Is Fading
The key trigger for this reversal was the failure of Japanese authorities' currency intervention to hold the yen against its decline. This week, the JPY exchange rate fell by approximately 1%, reaching 159.43 per dollar. This is the worst weekly result since May. The currency has already lost about half of the gains that followed the coordinated BoJ intervention in late July and early August. Before those measures, the rate was holding around 164 per dollar.
The historical context only heightens the concern: after the April intervention, the yen slid back to a 40-year low in the following months. It appears that one-off measures without a change in fundamental policy no longer work.
Traders Are Betting on a Rate Hike
Former top Tokyo currency diplomat Mitsuhiro Furusawa hinted in his comments that authorities are ready to deploy currency reserves at any moment. However, more importantly, he suggested the possibility of a faster rate hike to support the national currency. It is this connection between interventions and key rate decisions that explains the sharp shift in market expectations.
OCBC strategist Sim Moh Siong notes that interventions alone will not reverse the yen's dynamics. "It's no surprise that the yen has given up ground again," he said. In his assessment, the currency 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 approaches the target level.
My analysis: The market seems to have concluded that verbal interventions and one-off injections are a thing of the past. Investors want to see real action from the BoJ. However, the opposite scenario carries serious risks: if the regulator leaves the rate unchanged, disappointment will be immediate, and the yen could collapse to 160 per dollar. Right now, the market is pricing in central bank steps, not new currency interventions. This makes the September meeting one of the most important for the Japanese economy in recent years.