The U.S. September CPI data, due tonight at 8:30 p.m. Beijing time, is the last key inflation report before the Fed’s late-October policy meeting, and is drawing intense market attention. Most of the expected jump in headline inflation is already priced in; the extent to which core CPI deviates from expectations will be the real market catalyst tonight.
Data expectations: Headline inflation is set to jump; core is the focus
The consensus expects headline CPI to rise 0.6% month over month in September (previous: 0.4%), with the annual rate climbing from 3.4% to 3.6%, mainly due to a sharp rebound in gasoline prices.
By contrast, expectations for core CPI (excluding food and energy) are relatively subdued: around 0.2% month over month (previous: 0.3%) and around 2.5% year over year (previous: 2.4%). Forecasts for core inflation vary widely, ranging from 0.16% at Deutsche Bank to 0.24% at Goldman Sachs and Barclays. The jump in headline inflation is already priced in; the key driver of market pricing will be how far the core data deviates from expectations.
Scenario analysis: Core CPI will determine the direction of U.S. stocks
Scenario 1: Core CPI comes in below expectations (≤0.16%) — bullish for U.S. stocks
JPMorgan’s trading desk expects the S&P 500 to rise by about 0.5%–1% if core CPI comes in at 0.15%–0.20%. Historical data also shows that when core CPI has come in below expectations, the S&P 500 has risen by an average of 0.65% on the first trading day after the release, gained a cumulative 1.23% by the fifth trading day, and gained a cumulative 3.73% by the 20th trading day.
Scenario 2: Core CPI comes in line with expectations (around 0.20%–0.25%) — modest gains
JPMorgan expects the S&P 500 to rise by about 0.25%–0.75%, even in the baseline range of 0.20%–0.25%. Bank of America Securities economists believe that if the monthly core reading is 0.2%, market expectations for rate hikes will not rise significantly, and the Fed will most likely pause rate hikes in October.
Scenario 3: Core CPI comes in above expectations (≥0.25%) — pressure on U.S. stocks
JPMorgan expects the S&P 500 to fall by about 0.5%–1.25% if core CPI comes in at 0.25%–0.30%. If it exceeds 0.30%, the decline could deepen. Historically, when core CPI has exceeded expectations, the S&P 500 has risen by an average of just 0.05% on the first trading day after the release and fallen by an average of 0.36% by the fifth trading day.
Institutional views: Significant disagreement
Morgan Stanley (optimistic): Chief U.S. equity strategist Wilson believes the bond market has already done some of the Fed’s tightening for it. If CPI is moderate, the constraints weighing on U.S. stocks could ease, and gains may spread from AI leaders to more sectors. He is paying particular attention to financial stocks, whose performance he sees as a leading indicator of whether the market has shaken off the bond market’s impact.
Canadian Imperial Bank of Commerce (hawkish): Chief economist Shenfeld expects core inflation to rise 0.3% month over month and believes the Fed will raise rates this month, saying that “price growth in too many categories remains above 3%.”
Wealth Consulting Group (looking beyond CPI itself): Jimmy Lee believes the main concern in 2026 is not inflation but an economic slowdown. Regardless of the CPI reading, cyclical sectors (materials, industrials, and financials) are currently the most attractive choices.
Sector impact: Tech stocks are most sensitive to inflation
The Nasdaq typically reacts more sharply to inflation data than the Dow and the S&P 500 because its index weight is concentrated in high-growth, long-duration assets. If inflation data raises expectations that interest rates will stay higher for longer, pressure on tech valuations will become apparent.
If CPI comes in hot, real assets such as energy and commodities may benefit; if CPI is moderate, growth-oriented tech stocks and financials may have a chance to rebound.
The key takeaway for tonight’s CPI report is that a jump in headline inflation is already priced in, and any deviation in the core data will amplify market volatility. A softer core reading could allow U.S. stocks to extend their gains, while a hotter reading could trigger a short-term sell-off, particularly in rate-sensitive tech stocks.$AAPL $NVDA
