The Bank of Japan (BOJ) received fresh evidence that inflation is becoming more entrenched in the world's fourth-largest economy. The central bank's "trend inflation index" rose 3.2% year-on-year in September, the fastest pace since October 2023, according to data released just before the BOJ's policy meeting concludes on Friday.
The index is designed to filter out temporary effects, such as government subsidies that lower energy bills, to reveal the underlying inflation driven by domestic demand. The September reading suggests price pressures are broadening across the economy, making it harder for the BOJ to argue that inflation will cool on its own.
What is the trend inflation index?
The BOJ introduced this gauge to get a clearer picture of the inflation that matters for monetary policy. Unlike the headline consumer price index, which can be swayed by volatile items or government interventions, the trend index strips out those distortions. It focuses on the price changes that reflect the strength of demand in the economy.
When the trend index rises, it signals that businesses are able to pass on higher costs to consumers because spending is robust. That is a key condition for the BOJ to consider raising its benchmark interest rate, which currently sits near zero.
Japan has been an outlier among major economies for decades, struggling with deflation and weak price growth. But over the past year, inflation has consistently exceeded the BOJ's 2% target, and the central bank has begun to normalize policy, gradually moving away from its ultra-loose stance.
Why this matters for the BOJ's decision
The timing of the data is significant. The BOJ's policy board is meeting this week, and the September trend inflation figure will be a key input into their deliberations. Economists surveyed by Reuters had already expected the BOJ to consider a rate hike, and this latest reading strengthens that case.
If the BOJ decides to raise rates, it would mark another step in Japan's monetary policy normalization. The central bank has been cautious, wary of choking off the fragile economic recovery. But with inflation proving stickier than initially expected, the pressure to act is mounting.
Some analysts point to the recent rise in Japan's 10-year government bond yield, which climbed to 2.795% amid an AI-driven stock rebound, as a sign that markets are already pricing in tighter policy. Higher bond yields can also feed into the cost of borrowing for businesses and households, adding another layer to the BOJ's decision-making.
What it means for investors
For everyday investors, a BOJ rate hike would have several ripple effects. First, it could strengthen the Japanese yen, which has been weak against the dollar and other major currencies. A stronger yen can affect the profits of Japanese exporters, as their overseas earnings are worth less when converted back to yen.
Second, higher interest rates in Japan could impact global bond markets. Japanese investors are major buyers of foreign bonds, and if yields in Japan rise, they may shift money back home, potentially affecting bond prices elsewhere.
Third, the BOJ's move could influence other central banks. If Japan, the last major holdout of ultra-loose policy, starts tightening, it could signal that global inflation is becoming more persistent, prompting other central banks to keep rates higher for longer.
For investors with exposure to Japanese equities, the picture is mixed. Banks and financial institutions often benefit from higher interest rates, as their lending margins improve. On the other hand, companies that rely heavily on domestic consumption might see their costs rise, and exporters could face headwinds from a stronger currency.
It's also worth noting that Japan's economy has shown resilience, with Moody's recently suggesting that growth is turning durable, though a shock could test it. The BOJ will be balancing the need to control inflation against the risk of derailing that recovery.
As the policy meeting concludes on Friday, investors will be watching closely for any signals about the pace of future rate hikes. Some former BOJ officials, including ex-governor Haruhiko Kuroda, have even backed faster hikes than his former deputy, indicating that the debate within the central bank is lively.
For now, the trend inflation index has given the BOJ a solid reason to act. Whether it does so this week or later, the direction is clear: Japan's era of ultra-cheap money is coming to an end, and investors need to adjust to that reality.
