The market is pricing in an 84% probability of a rate hike by the Bank of Japan in September — what is happening with the yen
Participants on the decentralized prediction platform Polymarket have sharply revised their expectations regarding Japan's monetary policy. In just two weeks, the probability of a rate hike by the Bank of Japan at its September meeting has surged from 22% to 84%. This is a signal that no trader watching the currency market and global risk assets, including cryptocurrencies, can afford to ignore.
Why the yen is weakening again
The trigger for this shift in expectations was the fading effect of currency interventions by Japanese authorities. This week, the yen lost about 1% against the U.S. dollar, falling to 159.43. This is its worst weekly performance since May. Essentially, the currency has retraced roughly half of the gains recorded after the coordinated interventions in late July and early August, when the exchange rate hovered near 164.
The historical pattern is repeating itself: after the April intervention, the yen slid back toward a 40-year low over the following months. This suggests that one-off measures without a change in fundamental monetary policy are unable to alter the trend.
Betting on the central bank's resolve
Tokyo's former top currency diplomat Mitsuhiro Furusawa recently emphasized in comments that authorities are ready to deploy currency reserves at any moment. However, according to him, a more effective signal for the market would be an acceleration in the pace of rate hikes. This is precisely what traders are now pricing in, judging by Polymarket quotes.
OCBC strategist Sim Moh Siong notes that the yen is unlikely to hold without clear support from the Bank of Japan. Inflation in the country is approaching the target level, creating conditions for policy tightening. The market appears to have stopped believing in the effectiveness of new interventions and is now betting specifically on central bank moves.
"It's no surprise that the yen has given up ground again," Siong said, emphasizing that only clear action from the regulator can stabilize the currency.
Risks of the reverse scenario
The reverse scenario should also be considered. If the Bank of Japan keeps rates unchanged at its September meeting, market disappointment could be immediate. In the past, such decisions have already led to the yen falling to 160 per dollar. Currently, market participants are betting on the regulator's resolve, and any hint of a pause could trigger a new wave of volatility that would also affect global risk asset markets.
My view: The sharp jump in probability on Polymarket is not just speculation but a reflection of a real shift in institutional players' expectations. However, 84% is already a very high price for confidence. If the Bank of Japan disappoints the market, the correction could be painful, and this would create additional pressure on risk assets, including bitcoin. Keep a close eye on statements from board members in the coming weeks—they will determine the direction of the move.