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 actions. The probability of a key interest rate hike at the September meeting is estimated by the market at 84%. Just two weeks ago, this figure stood at only 22%.
This rapid shift in sentiment occurred against the backdrop of a weakening effect from the Japanese authorities' currency interventions. The yen has lost a significant portion of its recent gains and is posting its worst weekly performance in three months, increasing pressure on the regulator.
Intervention Effect Fades
This week, the Japanese currency has declined by approximately 1%, reaching 159.43 yen per dollar. This is the worst weekly result since May. Notably, the yen has already given back about half of the gains recorded after the coordinated currency intervention by the Bank of Japan in late July and early August. Before these measures, the exchange rate held around 164 yen per dollar.
A similar picture was observed earlier: after the April intervention, the yen retreated to forty-year lows in the following months. This points to the limited effectiveness of one-off measures without a change in fundamental monetary policy. Currency reserves cannot endlessly counter market trends, and market participants are well aware of this.
Market Bets on Policy Tightening
It is precisely the link between interventions and key rate decisions that explains such a sharp shift in expectations. Traders on Polymarket now price in a probability of a quarter-point rate hike above 80%.
Significantly, even Tokyo's former top currency diplomat Mitsuhiro Furusawa does not rule out the renewed use of currency reserves at any moment. In his assessment, the authorities are also ready to signal a faster rate hike to support the national currency. However, as strategists rightly note, interventions alone are insufficient to reverse the trend—clear support from monetary policy is needed.
Inflation in Japan is gradually approaching the target level, creating favorable conditions for policy normalization. At the same time, the opposite scenario carries significant risks: if the regulator leaves the rate unchanged, the market could react with sharp disappointment, and the yen could once again head toward 160 per dollar.
My analysis: The current yen dynamics are a classic example of the market testing the central bank's resolve. One-off interventions without a change in interest rate policy are perceived as a temporary measure rather than a shift in course. Given that inflationary pressure in Japan persists and a weak yen amplifies imported inflation, a September rate hike looks not just likely but almost inevitable to maintain confidence in the regulator's policy. For the crypto market, this is a signal of a possible yen strengthening, which could exert short-term pressure on risk assets, including bitcoin.