Revised Japan Q2 GDP data to influence BOJ September hike outlook

A positive revision to capital expenditure would strengthen the already high probability of a BOJ rate increase this month, supporting the yield spread narrative that has prevented the yen from weakening further despite recent softness. JGB yields, which are already at their highest in decades, would probably climb further on a better-than-expected reading, pressuring valuations in rate-sensitive areas of the Nikkei while exporters gain from the stronger growth story.

A downward revision would have the opposite effect: confidence in a rate hike would diminish, the yen would likely weaken again, and stocks might enjoy a temporary rally on lower tightening expectations.

Regardless of the result, USD/JPY and Nikkei futures remain sensitive to the data during the release period.

---

The GDP revision released today is more significant for the cover it provides the BOJ to raise rates this month than for the headline figure itself.

Summary:

• The initial Q2 GDP reading came in at 0.3% quarter-on-quarter and 1.1% annualised, undershooting the 0.5% and 2% forecasts respectively
• Capital spending declined 1.2% in the first estimate, versus a predicted 0.4% increase
• Private consumption showed no growth, marking the first time in eight quarters it has been flat
• Last week's strong corporate capital expenditure and profit figures suggest today's data is likely to be revised upward
• Markets are pricing approximately an 80% probability of a BOJ rate increase at the September 17-18 meeting
• The benchmark 10-year JGB yield has risen to a 30-year peak of around 2.925% as rate hike expectations intensify

Japan's Cabinet Office is releasing the second estimate of second-quarter GDP today, a revision that is unusually important because it comes just before the BOJ's September policy meeting (September 17–18, 2026). The initial estimate, published in mid-August, indicated the economy grew at an annualised rate of 1.1%, significantly below the 2% consensus, and 0.3% quarter-on-quarter, missing the 0.5% forecast. Domestic demand was the weak spot, with capital expenditure dropping 1.2% versus an expected modest increase, and private consumption unchanged for the first time in eight quarters.

The argument for an upward revision has gained momentum since the initial release. Last week's corporate capex and profit survey data showed companies increasing spending more than the preliminary GDP figures suggested, and capex components have historically been revised upward once more complete survey data arrives. A significant increase in the capex number could bring the annualised growth rate nearer to, or even above, the original 2% forecast that the preliminary figure missed.

The implications for monetary policy are direct. The BOJ convenes on September 17 and 18, with overnight swaps indicating about an 80% chance of a rate hike at that meeting, and some reports indicate the central bank may consider accelerating the pace of tightening afterwards. A stronger GDP revision, especially if driven by business investment rather than temporary trade factors, would strengthen the argument that the economy can handle higher borrowing costs, providing the BOJ with more justification to act.

Market impact is expected to come through two main routes. JGB yields, with the 10-year benchmark already at a 30-year high near 2.925%, would likely rise further on a strong reading, tightening financial conditions and putting pressure on rate-sensitive Nikkei sectors, while exporters benefit from the solid growth narrative. The yen, which has been trading cautiously despite the already-priced-in rate hike probability, would likely gain support from a print that clears up uncertainty about the BOJ's near-term policy. A downside surprise would have the opposite effect, reducing rate hike conviction, weakening the yen again, and potentially giving equities a brief respite from tightening-related pressure.