September CPI Rises 3.7% as Core Inflation Runs Hot

The September consumer price index, released by the Bureau of Labor Statistics at 8:30 a.m. Eastern on Wednesday, rose 0.6% for the month and 3.7% from a year earlier. The annual rate is up from 3.4% in August and came in above the 3.6% headline reading Bloomberg had penciled in, matching the more conservative 3.7% estimate from RBC. The real surprise was underneath: core CPI, which strips out food and energy, rose 0.3% for the month to a 2.6% year-over-year rate, hotter than the 0.2% monthly and 2.5% annual figures economists expected.

An energy-driven headline was the consensus framing heading into this release. That part held up: the energy index climbed 5.2% for the month and gasoline jumped 9.1%, accounting for about half of the entire increase in the headline number, according to the BLS. The national average for regular gasoline sat at $4.354 a gallon in the week ended October 5, per weekly EIA data, with gasoline up 34.2% over the past year and fuel oil up 74.2%. The supply-side role of Hurricane Isaias, flagged in our preview as the swing risk, shows up in those energy lines.

Related reading: September CPI Report Preview: Energy Headline vs Cooling Core, the Print That Decides October Hike Odds.

What made this release uncomfortable for markets was that it was not only a fuel story. Core inflation ran to 2.6% year over year against a 2.5% estimate, with shelter up 0.4% for the month, used car and truck prices up 0.7%, and apparel up 0.3% and 3.4% from a year earlier. The contained-core thesis that carried the consensus preview read did not survive the print. That is the delta that matters: it says the September acceleration is not something the Fed can wave off as a Hurricane Isaias one-off.

Related reading: September CPI Preview: Consensus Finds a Contained Core, With Isaias the Swing Risk.

For the broader framework, see our Fed policy coverage.

The first market response reflects that re-pricing. Equities sold off into the release: the S&P 500 fell about 0.8% and the Nasdaq 100 about 1.2%, with the small-cap Russell 2000 down roughly 1.3%. Long Treasuries fell as yields rose, the 20+ year fund TLT trading at $78.24, down 0.2%, and the 10-year Treasury yield up roughly 5 basis points to about 5.26%, near levels that cap equity multiple expansion. The dollar strengthened, with the Invesco DB USD Index fund (UUP) up about 0.7%, and the risk-off tone spread to metals and crypto: gold futures near $4,125, down 1.3%, and bitcoin near $81,650, down 1.7%. Higher-for-longer was the read across every asset.

What this confirms and what it breaks in our existing coverage: it confirms the FOMC call we laid out before the print. The meeting of October 27-28 was already a genuine question after September's 25 basis point hike to 3.75% to 4.00%, Chair Kevin Warsh's first of the cycle. It breaks the premise that a strong jobs market is the only thing standing between the Fed and another hike, and equally it weakens the opposite case that weak payrolls guarantee a pause. Friday's report had added just 29,000 jobs with unemployment at 4.2%, which had cut October-hike odds to roughly 20%. This core print moves the math the other way: futures markets now imply roughly 54% odds of a hike at the October meeting, per CME FedWatch, with better than 96% odds priced by year end. Money supply data reinforce the risk, with M2 growing 5.66% year over year in August, its fastest pace since 2021.

Related reading: Gas Hits $4.48 as August Shelter Costs Rise and FOMC October Meeting Hinges on CPI.

The bull case says the worst of this is transitory. The headline acceleration is dominated by a single energy month, Hurricane Isaias is a named, dated supply shock, food prices were flat for the month and up just 2.5% from a year earlier, and the labor market is clearly cooling toward 4.2% unemployment. If energy normalizes next month, the base effect alone pulls the annual headline lower, and a Fed that hiked once into a slowing labor market may hold to watch the data.

The bear case is that core inflation at 2.6% and re-accelerating is not a fuel artifact, and that a second consecutive hike is now the live scenario. Shelter at 0.4% monthly is sticky, used cars jumped, and core PCE, which the Fed prefers, is already running at 3.01% year over year. With M2 growing at its fastest clip in years and core inflation running above target, the tightening path has room to extend even with the labor market softening. That is why the market sold risk assets into a print many chalked up to gasoline.

What to watch next: the October 27-28 FOMC decision, and in the interim the path of gasoline prices as the Isaias supply shock unwinds, the October core PCE reading, and whether the 54% October-hike odds in futures hold or fade. For the household, the number that lands this week is the clock on refinancing and credit: a second hike keeps mortgage and card rates pinned near multiyear highs. The decisive question is whether the core number is one month of noise or the start of a trend. That, not the Hurricane Isaias energy spike, is what the Fed will be debating when it meets.

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