The Japanese yen extended its rally Tuesday, reaching 152.89 per dollar before giving back some gains to trade around 153.32. The move pushed the currency beyond levels reached during Japan’s July intervention and marked its strongest point since February.

The latest advance follows a 1.2% gain Monday and leaves the yen approximately 4.5% stronger than its level near 160 per dollar at the beginning of last week. The speed of the move suggests that positioning, rather than a single economic catalyst, is driving the shift.

Traders are increasingly betting that the Bank of Japan could accelerate monetary tightening. At the same time, Japanese investors may begin repatriating overseas funds, while carry trades that benefited from borrowing cheaply in yen are being unwound. The combination is putting pressure on investors who had maintained bearish positions against the currency.

Could the Yen Rally Become Self-Reinforcing?

The currency’s rapid appreciation is creating a feedback loop in foreign-exchange markets. As key technical levels break, stop-loss orders can force traders with short-yen positions to buy the Japanese currency, potentially accelerating the move.

ANZ Asia research head Khoon Goh noted that the initial strengthening appeared to trigger significant stop-loss activity. He identified 150 yen per dollar as the next important level for markets to monitor, while emphasizing that the continuation of the rally could depend on how many short positions remain open.

The dollar index was slightly weaker at 98.83, while the euro and pound were largely unchanged near $1.1625 and $1.3535, respectively. The contrast underscores the yen’s unusually strong performance rather than a broad collapse in the dollar.

China’s yuan was also stable near 6.71 per dollar, around a three-and-a-half-year high, following stronger-than-expected export growth in August.

Why Could US Inflation Data Determine the Next Currency Move?

Attention is now shifting toward US inflation data, which represents one of the final major economic inputs before the Federal Open Market Committee meets September 15–16. Markets are currently pricing roughly a 60% probability of a Federal Reserve rate hike this month after stronger-than-expected US payroll data last Friday.

A hotter CPI reading could reinforce expectations for tighter US monetary policy and potentially support the dollar, while softer inflation could reduce pressure for additional tightening. That makes the data particularly important for the yen, where the direction of US rates intersects with growing expectations for a more hawkish Bank of Japan.

Meanwhile, geopolitical risks are complicating the inflation outlook. Iran has warned that Gulf energy infrastructure, including US oil and gas interests, could be vulnerable to retaliation following further American attacks. Brent crude remains firmly above $97 a barrel near a six-week high.

For currency investors, the critical question is whether the yen can break through 150. A sustained move below that threshold could signal a deeper unwinding of bearish yen positioning, while stronger US inflation or renewed geopolitical volatility could interrupt the rally.