The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September.
Polymarket's prediction market has dramatically shifted its assessment of the Bank of Japan's actions: the probability of a key interest rate hike at the September meeting now stands at 84%. Just two weeks ago, this figure was at 22% — such a rapid reversal in expectations points to deep changes in how traders and analysts perceive the regulator's monetary policy.
Yen Loses Gained Ground
The key catalyst for this shift was the weakening effect of Japanese authorities' currency interventions. This week, the yen fell by approximately 1%, reaching 159.43 per dollar, marking its worst weekly performance since May. The currency has already lost about half of the gains it posted following the Bank of Japan's coordinated currency interventions in late July and early August, when the exchange rate was held around 164 yen per dollar.
This dynamic is not new: after the April intervention, the yen retreated to a 40-year low in the following months. This confirms that one-off measures without changes to fundamental policy cannot provide sustainable support for the national currency.
Betting on Decisive Regulator Action
The link between interventions and key rate decisions explains the sharp shift in expectations. Market participants are now betting that the Bank of Japan will be forced to move to more decisive measures than targeted currency interventions. Inflation in the country is approaching the target level, creating conditions for monetary policy tightening.
The opposite scenario carries significant risks: if the regulator leaves the rate unchanged, the market will react with disappointment, and the yen could fall again to 160 per dollar. This is why traders are now focusing on the central bank's steps rather than possible new interventions.
My analysis: The sharp jump in probability on Polymarket reflects not just speculative activity, but a real change in market consensus. However, it is worth remembering that the Bank of Japan has historically shown caution in tightening policy. If the regulator fails to meet market expectations in September, we could see not only a weaker yen, but also increased volatility in global markets, including the cryptocurrency market, since the yen remains a key factor for carry-trade strategies.