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 revised their expectations regarding the Bank of Japan's monetary policy. In just two weeks, the probability of a key interest rate hike at the September meeting has surged from 22% to an impressive 84%. This signals a dramatic shift in market sentiment, which now has virtually no doubt about the regulator tightening its policy.
Failed interventions and yen weakness
The main catalyst for this turnaround has been the ineffectiveness of currency interventions by Japanese authorities. Despite massive injections to support the national currency, the yen continues to depreciate. This week, the USD/JPY exchange rate fell by approximately 1%, reaching 159.43, marking the worst weekly performance in the last three months. In essence, the currency has given back half of the gains recorded after the coordinated intervention in late July and early August, when the rate was held around 164 per dollar.
Notably, a similar pattern was observed earlier: after the April intervention, the yen slid back to its multi-year lows within a few months. This confirms that one-off measures cannot change the fundamental trend of currency weakening.
Betting on central bank action
The market is coming to understand that the only effective tool to support the yen could be a real tightening of monetary policy. Tokyo's former top currency diplomat Mitsuhiro Furusawa has directly stated that authorities are ready to deploy currency reserves at any moment and may also signal a faster rate hike to support the currency. This stance resonates with market participants.
OCBC strategist Sim Moh Siong rightly notes that interventions alone will not reverse the yen's dynamics. "It's no surprise that the yen has given up ground again," he emphasizes. In his view, the Japanese currency needs clear support from the Bank of Japan, which is ready to tighten policy as inflation approaches its target level. This view fully aligns with growing expectations of a faster rate hike.
However, the opposite scenario also carries significant risks. If the regulator leaves the rate unchanged, the market will quickly react with disappointment, and the yen could once again plunge to the 160-per-dollar level. Market participants are now betting on central bank steps rather than new currency interventions.
My take: The sharp jump in probability on Polymarket is not just a speculative move but a reflection of a real change in the market paradigm. Traders and investors no longer believe in "manual management" of the exchange rate and demand decisive action from the Bank of Japan. If the regulator meets expectations, we could see a significant strengthening of the yen, which would pressure the Japanese stock market and likely resonate in global risk assets, including cryptocurrencies.