Currency traders are bracing for potential intervention by Japanese authorities, with the window for action expected to open around the upcoming central bank policy meeting and the subsequent market holiday that thins out liquidity.

The yen strengthened as much as 0.5% to 157.99 per dollar on Thursday as market participants began pricing in the possibility of a rate hike exceeding 25 basis points at the Bank of Japan's next gathering. The currency also jumped 1.2% during Wednesday's New York session, underscoring the heightened nerves ahead of the September 18 policy announcement, where a move higher in rates is broadly anticipated.

Japan's last intervention in April came after officials waited for the domestic holiday period to begin, marking the first such action in 2024. Investors now suspect the authorities may repeat that playbook during the Silver Week holiday stretch, which starts shortly after the BOJ's decision.

Commonwealth Bank of Australia strategist Samara Hammoud noted that Silver Week could inject added volatility into yen trading, primarily due to thinner market participation during the break. The dollar-yen pair is likely to test pre-intervention peaks again, and if that occurs, especially around the time of the BOJ meeting, the likelihood of another round of official action rises markedly.

Even after Japan deployed a record $96.4 billion to shore up the yen over the past month, the currency remains under pressure from elevated oil prices and the substantial interest-rate differential with the United States. Washington has also thrown its weight behind Tokyo's efforts, reinforcing a clear warning to speculators betting against the yen.

Both Japanese Finance Minister Katsunobu Katayama and U.S. Treasury Secretary Scott Bessent have signaled readiness to act again without hesitation if conditions warrant. Meanwhile, speculative positioning is shifting back toward short yen bets, as hedge funds that slashed bearish positions following the intervention are now rebuilding those negative wagers.