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 Japan's monetary policy. In just two weeks, the probability of the Bank of Japan raising its key interest rate at the September meeting has surged from 22% to 84%.
This shift in market sentiment occurred after the effect of recent currency interventions by Japanese authorities began to fade. The yen, which had previously shown steady gains, is now losing its acquired positions and heading toward its most significant weekly decline in three months.
The Weakness of Interventions Is Becoming Obvious
This week, the yen has fallen by approximately 1%, reaching 159.43 against the dollar. This is the worst weekly performance since May. Notably, the currency has already given back about half of the gains achieved following the coordinated currency intervention by the Bank of Japan in late July and early August. Before those measures, the exchange rate held around 164 yen per dollar.
A similar pattern was observed earlier: after the April intervention, the yen retreated to 40-year lows in the following months. This confirms that one-off targeted interventions without changes to fundamental policy cannot provide sustainable support for the national currency.
Significantly, former top Tokyo currency diplomat Mitsuhiro Furusawa indicated in his comments that authorities are ready to deploy currency reserves at any moment. However, he also pointed to the possibility of sending the market a signal about a faster rate hike — which, in his view, could be an effective tool to support the yen.
Traders Bet on Policy Tightening
The connection between interventions and key rate decisions explains such a sharp shift in expectations. Polymarket participants now estimate the probability of a quarter-point rate hike at more than 80%. This consensus is also supported by the views of professional strategists.
According to analysts' estimates, interventions alone are insufficient to reverse the yen's dynamics. The currency pair needs clear support from monetary policy, namely the regulator's readiness to tighten lending conditions. This approach aligns with growing expectations of a faster rate hike, especially as inflation approaches the target level.
The opposite scenario carries significant risks. If the Bank of Japan leaves the rate unchanged, the market could react with sharp disappointment — the yen has already shown declines to 160 per dollar in similar situations. Currently, market participants are betting on central bank actions rather than new currency interventions.
Analyst's comment: The sharp jump in the probability of a rate hike on Polymarket reflects not just speculative activity, but the market's fundamental understanding of the limitations of intervention measures. However, it is worth remembering that prediction platforms are sensitive to short-term news flows. If the Bank of Japan shows caution, we could see an equally rapid correction of expectations in the opposite direction.