The Japanese yen is under pressure: the market is pricing in an 84% probability of a rate hike 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 rate hike in September has surged from 22% to 84%. This is a signal that no trader working with Asian markets can afford to ignore.
The root of this shift in sentiment lies in the rapid fading of the effect of recent currency interventions by Japanese authorities. The yen, which strengthened from around 164 per dollar after coordinated support measures in late July and early August, has now given back roughly half of its gains. This week, the exchange rate fell by about 1%, reaching 159.43 per dollar—the worst weekly performance since May.
Why interventions no longer work
History shows that one-off interventions are not a panacea. After April's injections, the yen slid back to 40-year lows within a few months. We are now witnessing a repeat of this scenario: the market is testing the regulator's resolve, and the fact that the yen has given back half of its gains suggests that traders no longer believe in the effectiveness of targeted measures.
Notably, even Tokyo's former top currency diplomat Mitsuhiro Furusawa recently acknowledged the possibility of using currency reserves again. However, he emphasized that authorities could also opt for a faster rate hike—and that is precisely the signal the market is waiting for. Traders reasonably reason: if interventions only temporarily curb pressure, then the only effective tool left is monetary policy tightening.
Betting on the central bank instead of interventions
The link between interventions and rate decisions is now obvious to everyone. OCBC strategist Sim Moh Siong notes that the yen's retreat is expected, and for a sustained reversal, it needs clear support from the Bank of Japan, ready to tighten policy. This view aligns fully with rising expectations of a faster rate hike, especially amid inflation approaching the target level.
The opposite scenario carries serious risks. If the regulator leaves the rate unchanged, the market will quickly react with disappointment—the yen has already shown drops to 160 per dollar after similar decisions. Currently, traders are betting on central bank action rather than new currency interventions, and this shift in expectations is a key factor for forecasting the exchange rate in the coming weeks.
My view: The market seems to have finally set its priorities straight. Currency interventions in the modern economy are merely anesthesia, not a cure. If the Bank of Japan fails to meet expectations in September, we could see not just a weakening yen, but a full-blown currency crisis that would also affect crypto markets, given the yen's correlation with risk assets. Keep a close eye on the rhetoric of board members in the coming weeks.