During Wednesday's Asian trading session, the dollar strengthened against the yen with a modest 0.2% gain, hovering near 155.40 and briefly touching a fresh high of 155.48, a level not seen since September 8th. The market anticipates the Federal Reserve will raise interest rates by 25 basis points to a range of 3.75% to 4.00%, marking its first increase in three years. Meanwhile, the Bank of Japan is projected to follow suit on Friday with a 25 basis point hike to 1.25%, which would represent the highest borrowing costs since April 1995. For determining the yen's short-term trajectory, the policy tones and forward guidance from both institutions will prove more crucial than the rate changes themselves.

Federal Reserve: Rate Hike Widely Expected, Market Focus on Post-Meeting Tone

Recent U.S. inflation data released last week has shown considerable persistence, with core inflation — which strips out volatile food and energy components — climbing further on a month-over-month basis in August. This has notably reinforced market expectations for imminent tightening action from the Federal Reserve. Current market consensus overwhelmingly points to a 25 basis point rate increase at this week's Wednesday Federal Open Market Committee meeting, lifting the benchmark overnight rate to the 3.75% to 4.00% range. This marks the Fed's first rate increase in three years, carrying significant symbolic weight as a policy signal.

With the rate hike itself being essentially a foregone conclusion, traders are shifting their focus to the post-meeting press conference, particularly the remarks from Federal Reserve Chair Kevin Warsh. Market participants will meticulously analyze his assessment of the inflation outlook, labor market conditions, economic growth prospects, and the future rate trajectory to gauge whether this increase represents a one-time adjustment or marks the beginning of a sustained tightening cycle. Should Warsh and other committee officials deliver unmistakably hawkish signals — emphasizing that inflation risks have yet to subside, hinting at potential further hikes, or raising their estimates for the neutral rate — the dollar could gain substantial support, potentially pushing USD/JPY higher in the near term. Conversely, if the statement and press conference adopt a more cautious stance, stressing data-dependence or pointing to signs of slowing economic growth, dollar gains could be constrained. U.S. Treasury yields, currently elevated due to rate hike expectations and oil-related inflation concerns, are amplifying the potential market impact of the post-meeting tone.

Bank of Japan: Rate Increase Priced In, Guidance Becomes the Market Mover

The Bank of Japan is expected to raise its key policy rate by 25 basis points at its September meeting on Friday, from 1.00% to 1.25%, marking the country's highest borrowing costs since April 1995. Traders will closely monitor Governor Kazuo Ueda's statements regarding the pace of future rate increases and the upper limit of the current tightening cycle. Strategies at a well-known institution note that the BOJ's decision itself is unlikely to deliver a major surprise since the rate increase has been widely anticipated and thoroughly priced into the market. The genuine market driver will be the central bank's guidance on the tempo of future hikes, particularly given that another increase before year-end is almost fully priced in. The strategists believe the risk balance favors how firmly policymakers validate existing market expectations regarding the BOJ's tightening path. A chief currency strategist from another prominent institution suggests that even with this rate increase, the BOJ would find it difficult to strike a more hawkish stance than the market currently expects, flagging the risk of USD/JPY moving toward the 157 level.

Institutional Outlook

Strategists Chong Hoon Park and Nicholas Chia at Standard Chartered believe the BOJ is poised to raise rates by 25 basis points to 1.25% at its September 17-18 meeting while maintaining a gradual normalization path, avoiding any overly hawkish signals. They emphasize that BOJ tightening alone will struggle to drive meaningful yen appreciation since the recent supportive factors for the yen — including rate hike expectations and repatriation flow hopes — have largely been fully priced in by the market. Standard Chartered points out that the probability of significantly accelerated rate increases or a rapid shift in GPIF investment flows is low, making the market's threshold for negative surprises quite low. Based on this analysis, they project USD/JPY to recover toward the upper end of the 155-160 range in the fourth quarter. Elevated U.S. Treasury yields, supported by Fed rate hike expectations and oil-driven inflation risks, also continue to bolster the dollar.

Mitsubishi UFJ Financial Group (MUFG) maintains its baseline forecast for a gradual USD/JPY decline in its latest monthly foreign exchange outlook: 158 for the end of the third quarter, 156 for the fourth quarter, 154 for the first quarter of 2027, and 152 for the second quarter. They contend that the BOJ's September hike is nearly fully priced in, with expectations for two additional rate increases through mid-2027 already reflected in the market. Consequently, a single rate increase offers limited support for the yen. While some moderation in Fed tightening expectations contributes to dollar weakness, domestic Japanese factors — including a cautious pace of rate increases and still-negative real interest rates — will restrict the yen's appreciation potential. MUFG notes that if U.S. yields fail to decline noticeably or the BOJ's tightening pace remains slow, downside room for USD/JPY will be limited.

Summary: Battle of Spreads and Guidance Leaves Yen Under Pressure

In the broader picture, both the Fed's and BOJ's rate decisions are already substantially absorbed by the market, making the decisions themselves unlikely to generate directional breakthroughs. The true variable lies in the forward guidance from both central banks. If the Fed appears more hawkish than expected while the BOJ fails to deliver more aggressive tightening signals than the market anticipates, USD/JPY could push higher. Conversely, if the BOJ clearly reinforces its tightening path, the yen could gain temporary support. With both decisions pending, the 155 to 157 range represents the critical battleground for bullish and bearish forces in the currency market.

As of 10:07 Beijing time, USD/JPY was trading at 155.41/42.