The market is pricing in an 84% probability of a rate hike by the Bank of Japan: the yen comes under pressure again.
Participants in the decentralized prediction market Polymarket have radically 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 an impressive 84%. This is a signal that no trader working with Asian currencies can afford to ignore.
The reason for this reversal is the sharp weakening of the effect of currency interventions by Japanese authorities. The yen, which strengthened to around 164 per dollar after coordinated actions in late July and early August, has now given back a significant portion of those gains. This week, the USD/JPY exchange rate rose by about 1%, reaching 159.43. This is the worst weekly performance for the Japanese currency in the last three months.
The historical context only amplifies the concern: after the April intervention, the yen slid back to 40-year lows over the following months. The market is beginning to understand that one-off measures without changes to fundamental policy do not work.
Betting on the central bank's resolve
The key question now is whether the Bank of Japan will move from words to action. Tokyo's former top currency diplomat, Mitsuhiro Furusawa, has stated outright that authorities are ready to deploy currency reserves at any moment and may also signal a faster rate hike to support the national currency.
OCBC strategist Sim Moh Siong shares this skepticism regarding the effectiveness of interventions. In his assessment, the yen needs not one-off support, but a clear and consistent stance from the regulator, ready to tighten policy. Inflation in Japan is approaching the target level, which creates room for such a move.
However, the opposite scenario carries serious risks. If the Bank of Japan leaves the rate unchanged, market disappointment could trigger a new decline in the yen—down to the 160 per dollar level. Market participants are currently betting on the central bank's resolve, not on new interventions.
My view: The prediction market is not just a mirror of sentiment, but a powerful indicator of consensus. The rise in probability to 84% reflects not only the yen's weakness, but also the belief that the Bank of Japan is finally ready to abandon its ultra-low rate policy for the sake of currency stability. If the regulator meets expectations, we will see not only a strengthening of the yen, but also a wave of volatility across global markets, including the cryptocurrency market, where the yen is often used as a funding currency for carry trades.