August CPI: What to Watch as Inflation Data Lands

Markets expect the August Consumer Price Index to show headline inflation rising 0.2% month-over-month and 2.9% year-over-year, with core prices climbing 0.3% on the month. Those numbers put the Federal Reserve's September rate decision squarely in focus. The consensus from Bloomberg surveys as of September 6 shows inflation accelerating from July's 0.1% monthly increase, but the core reading still runs hot enough to keep policymakers cautious.

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For more on Fed policy and inflation, see our Fed policy coverage.

Shelter costs deserve the most attention in this report. The Bureau of Labor Statistics' Owners' Equivalent Rent component has driven core inflation for months, and there are early signs that housing markets are cooling. Apartment vacancy rates have edged up from their cycle lows, asking rents have moderated in major metros, and new lease growth has slowed. If those trends show up in the CPI data, it could mark a meaningful shift in the inflation narrative. Conversely, if shelter costs remain sticky, markets will have to price in a longer period of elevated rates.

Energy prices present another key variable. Gasoline prices fell roughly 4% in August according to AAA data, while natural gas retreated from summer peaks. Those declines should subtract from the headline figure, potentially masking underlying inflationary pressure in services. Market participants should look past the headline number to the core components and the six-month annualized rate, which gives a clearer picture of the inflation trend.

The Fed's preferred inflation gauge, the Personal Consumption Expenditures index, typically tracks CPI closely but with some sectoral differences. Medical care and recreation tend to carry more weight in PCE, while housing plays a smaller role. So a hotter CPI reading doesn't automatically mean a hotter PCE print, and vice versa. The central bank's latest Summary of Economic Projections shows officials expecting core PCE to end 2026 at 2.6%. August CPI data will either reinforce or challenge that baseline.

Market reaction hinges on the core reading and the three-month annualized trend. A core print below 0.2% would likely strengthen the case for a September rate cut, sending Treasury yields lower and boosting rate-sensitive sectors like homebuilders and utilities. A core print above 0.3%, or a six-month annualized rate above 3%, would push rate cut expectations further into the future. The futures market currently prices in roughly a 60% chance of a September cut, but that probability swings sharply on CPI surprises.

The labor market backdrop adds another layer of complexity. Unemployment has held steady near 4.0%, wage growth has moderated but remains above pre-pandemic levels, and job openings have declined from their 2022 peak without collapsing. That combination suggests the economy can withstand slightly higher rates without significant pain, giving the Fed room to stay patient on cuts. Labor market data in early September will matter as much as the CPI print for the September FOMC decision.

Risk factors to watch include upside surprises in medical care and recreation services, both of which have shown episodic strength this year. Auto insurance costs have also been a persistent contributor to CPI gains, and there is limited visibility on when that trend might reverse. On the downside, used vehicle prices have been a deflationary force for months, and that could continue if dealer inventories remain elevated.

What to watch on Friday: the core month-over-month reading, the six-month annualized core rate, the shelter component specifically, and the market's immediate reaction in 2-year Treasury yields and fed funds futures. The numbers will set the stage for the September 17 FOMC meeting and determine whether the Fed signals a rate cut or holds steady for another meeting.

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