Japan's August CPI due as BoJ rate hike looks all but certain

Japan's inflation numbers usually have only a minor direct effect on the yen and JGB yields when they come out on the same day as a Bank of Japan decision, and this occasion is no different. Traders are paying more attention to the BoJ meeting's outcome and Governor Ueda's press conference later today than to the CPI release, given that a rate increase is already almost fully accounted for in swap markets. A core CPI figure matching the 1.8% consensus would probably not shift that trajectory much, though a significant upside or downside surprise could still move USD/JPY and short-dated JGB yields in the hours before the policy announcement. Some analysts have also pointed to the possibility that yen intervention talk could resurface around the thin trading conditions of the Silver Week holiday period after the meeting.

Preview: BoJ rate hike bet stays intact as Japan awaits August CPI

Japan's August CPI data arrives as the BoJ gets ready to raise rates to their highest in 31 years, with the inflation number unlikely to change the outlook either way.

• Japan is set to release national CPI data for August on Thursday; the Tokyo reading from three weeks ago showed core inflation excluding fresh food at 1.8% year on year, up from 1.7% in July and matching forecasts
• Economists surveyed by Reuters project national core CPI will also stay at 1.8% for August, unchanged from July and still below the BoJ's 2% target
• Producer price inflation quickened to roughly a three-and-a-half-year high in August, suggesting rising upstream cost pressures
• The BoJ wraps up a two-day policy meeting on Thursday, with swap markets pricing in a near-certain 25 basis point hike to 1.25%, the highest level since 1993
• Thursday's CPI data is expected to be viewed as confirming the broader trend rather than a key factor for the board
• Governor Ueda will hold a press conference later on Thursday; a more detailed BoJ preview will be published separately

Japan is scheduled to publish its national consumer price index for August on Thursday, a release that will get less attention than usual because the Bank of Japan's own policy decision falls on the same day. The Tokyo area figures, which are considered a leading indicator for the national data, already provided traders with an early read three weeks ago: core CPI excluding fresh food rose 1.8% year on year in August, a slight increase from 1.7% in July and in line with the median forecast. A closely watched measure that strips out both fresh food and energy also ticked up, moving closer to the BoJ's 2% inflation target.

Economists polled by Reuters expect the national figure to follow that pattern, with core CPI predicted to stay at 1.8% year on year for August, unchanged from July and still below the central bank's target. A steady reading would continue a sequence of below-target core readings even as broader price pressure keeps building elsewhere in the economy. Producer prices, an upstream gauge of the costs that businesses eventually pass on to consumers, accelerated to their fastest pace in roughly three and a half years in August, strengthening the argument that inflation has further room to run once government fuel subsidies are phased out.

None of this is likely to be the decisive factor for the BoJ board, which concludes a two-day meeting later on Thursday. A quarter-point rate hike to 1.25% is almost fully priced in by swap markets, and the argument for tightening has already been constructed over recent months on the back of strong wage data, a weaker yen, and warnings from board members including Hajime Takata that the bank should act quickly if price pressure rises further. Thursday's CPI print will most likely be interpreted as confirmation of the broader trend rather than something the board is waiting for before making its move.

The bigger market event will be Governor Kazuo Ueda's press conference later on Thursday, where traders will scrutinise his comments for signals on the pace of further tightening beyond the expected move. A hike would lift Japan's policy rate to its highest level since 1993 and represent the BoJ's sixth increase since it exited ultra-loose policy in 2024. A separate, more comprehensive preview of the rate decision will be published later.