Wall Street will finally get U.S. inflation data for September, and the numbers could inject some more volatility into an already jittery stock market. The latest consumer price index report is set for release Friday at 8:30 a.m. ET. Economists in general expect headline CPI to have risen 0.4% month over month and 2.9% year over year. JPMorgan economist Michael Feroli sees core CPI, which strips out food and energy, having gained 0.3% from August. That would equate to a 3.1% gain year on year. However, if prices rise more or less than expected, it could send stocks ripping higher or lower — especially as investors pore through the data for clues on future Federal Reserve policy moves. JPMorgan’s trading desk broke down how stocks might react to the report, highlighting five scenarios along with their chances of becoming true: (35% chance) Core CPI rises 0.3%-0.35%: S & P 500 flat to 0.5% higher (30% chance) Core CPI rises 0.35%-0.4%: S & P 500 loses 0.5%-1.25% (25% chance) Core CPI rises 0.25%-0.3%: S & P 500 gains 0.75%-1.25% (5% chance) Core CPI rises more than 0.4%: S & P 500 loses 1.5%-2.25% (5% chance) Core CPI rises less than 0.25%: S & P 500 gains 1%-1.5% “The market is pricing a nearly 100% chance that the Fed cuts by 25bp next week. We agree with the market’s view and think it would take the largest of tail-risks to push the Fed to the sideline,” JPMorgan traders wrote. “However, if we see a hawkish print for Core Goods, then it may be worthwhile to consider that another inflation peak has yet to form. We think an inline to slightly hawkish print is most likely given the references to inflationary pressure across recent macro data, e.g., ISM / Flash PMIs.” ( Learn the best 2026 strategies from inside the NYSE with Josh Brown and others at CNBC PRO Live. Tickets and info here . )
