September’s Hot CPI Report Shows Price Pressures Broadening

Key Takeaways

• Inflation accelerated in September as oil supply shocks, AI demand, and resilient consumers put upward pressure on prices.
• Economists were particularly surprised by rising shelter prices, which account for about one-third of CPI and have been a key driver of disinflation in recent years.
• Wednesday’s data could force Fed officials to abandon the dovish tone they adopted in recent weeks.

The economy is running hotter than most thought, as seen in the September Consumer Price Index report, which showed broad price pressures that caused inflation to accelerate last month.

CPI increased 0.6% in September, a larger-than-expected uptick from August’s 0.4% increase. On a year-over-year basis, inflation accelerated to 3.7% (its fastest rate since May), up from 3.4%. Core CPI, which excludes volatile food and energy prices and is considered a more accurate indicator of underlying inflation trends, rose 0.3%, pushing the year-over-year core inflation rate to 2.6% from 2.4% in September.

The report was “certainly hotter than I expected, what the markets expected, what economists expected,” says Christopher Hodge, chief US economist at Natixis. “And, more troublingly, [the inflation] is broad-based.”

Wednesday’s report could spell trouble for the Federal Reserve as it attempts to return inflation to its 2% target without tipping the economy into recession. “Inflation pressures are broadening beyond energy, suggesting the last mile back to target could remain bumpy and keep interest rates elevated,” wrote Jeffrey Roach, chief US economist for LPL Financial.

September CPI Inflation Report Highlights

• CPI rose 0.6% for the month after increasing 0.4% in August.
• Core CPI rose 0.3% in September, as in August.
• CPI increased 3.7% year over year, up from 3.4% in August.
• Core CPI rose 2.6% over the year, up from August’s 2.4% increase.

Much of last month’s inflationary pressure stemmed from energy prices, as in August. Oil prices rose sharply as the conflict in the Middle East expanded, threatening to cut off the Red Sea routes Saudi Arabia has used to bypass the Strait of Hormuz. As a result, the gasoline index rose 9% in September, accounting for more than half of the CPI’s 0.6% monthly increase, according to Wednesday’s report.

While energy has driven inflation in recent months, non-energy prices surprised to the upside. Month-over-month core inflation held steady at 0.3%, defying expectations for a slowdown to 0.2%. Wednesday’s hot print put the annualized three-month core inflation rate at 3.4%, its fastest in a year, according to Morningstar chief US economist Preston Caldwell.

The pressure within core prices was alarmingly broad-based. “Core goods prices jumped, shelter inflation was noticeably above recent trends, and the component that everyone’s been fixated on—non-housing services—stayed elevated,” says Adam Schickling, senior economist at Vanguard.

Economists at Bank of America noted that, unlike August’s data, accelerating core goods and services inflation “cannot be traced to one or two idiosyncratic sources.”

Core goods prices rose to 0.3% from 0.1% in August. Used car prices jumped 0.7%, and recreational goods increased 0.9%. Information technology commodities rose 0.9%, “a spillover effect from demand related to the AI buildout,” according to Oxford Economics.

One possible silver lining: “We still do not see significant evidence of higher energy prices feeding through to core goods prices,” wrote Citigroup economists. The risk of businesses passing higher fuel costs along to consumers by raising prices, creating more pervasive and persistent inflationary pressures in the process, has been a major concern this year.

Schickling says inflation’s breadth speaks to “the continued pricing power that a lot of enterprises feel they have.”

But Wednesday’s data suggests some industries may be running out of runway. Despite rising jet fuel prices, airfares rose 1.2%, a modest increase compared with their 2.7% jump in August. “This could suggest the ability to raise these prices further is reaching a limit,” wrote Citigroup economists.

Shelter Inflation a Big Surprise

One of the bigger and more consequential surprises in Wednesday’s report was an uptick in shelter inflation. The 0.40% month-over-month increase in shelter prices contributed 0.15 percentage points to core inflation, or nearly half the monthly increase, according to Charlie Ripley, senior investment strategist at Allianz Investment Management.

Citigroup economists say September’s surprising print could be the result of a one-off anomaly. They note September 2025’s shelter inflation was unusually soft, and that most of last month’s increase was concentrated in the Midwest. “Shelter inflation can be very noisy,” says Schickling. Still, “we had been seeing some leading indicators of rent that were edging higher.”

Schickling says the jury’s out on whether September’s data signals shelter inflation picking up: “Shelter inflation has been this big disinflationary force for the last three years, so that’ll be an area we’ll keep an eye on over the next couple of months.”

Bank of America economists say the data at least “reaffirms our view that rent disinflation has run its course.”

What the September CPI Means for the Fed

The September CPI is one of the last inflation reads Fed officials will see before they meet to set interest rates at the end of this month, and economists say Wednesday’s report was not what they wanted. “The latest report complicates the Fed’s decision this month, as the road back to price stability is looking increasingly difficult to navigate,” writes LPL Financial’s Roach.

The Fed raised interest rates by a quarter point last month (its first hike since 2023) in response to stubbornly high inflation. Officials also signaled their willingness to continue raising rates, with the majority penciling in one more hike before the end of the year. Investors have been debating the timing of that hike ever since.

In recent weeks, dovish talk from officials and a disappointing September jobs report had markets betting that the Fed would leave rates unchanged later this month. Many economists, including Vanguard’s Schickling and Natixis’ Hodge, say they don’t expect Wednesday’s report to change the Fed’s tilt. However, Bank of America expects an October hike, and Citigroup, which once expected no changes through the end of the year, is now predicting a December hike.

Investors are significantly more uncertain now. The market odds of an October hike shot up to more than 50% Wednesday morning from 22% on Tuesday. “That may be a bit of an overreaction to a mere one month’s data,” says Morningstar’s Caldwell. (Those odds moderated to about 40% by Wednesday afternoon.) “Still, we do expect the Fed to hike one more time this year, in either the October or December meetings,” he says.

Economists point out that the market’s rate expectations can be consequential. “If markets continue to price in over a 50% chance of hikes, then [the Fed] might be bullied into it,” says Hodge.

Bank of America analysts say the Fed’s credibility could be at stake: “A Fed that fails to deliver a hike when markets are pricing a greater than 50% probability risks losing control of the long end [of the yield curve].”