Summary:
The September Consumer Price Index (CPI) report gains outsized importance due to the U.S. government shutdown’s data blackout. Wall Street anticipates a 0.4% monthly increase with annual inflation holding at 3.1%, while economists scrutinize tariff impacts on categories like household goods and autos. With no major economic releases preceding the Federal Reserve’s policy meeting, even minor CPI deviations could trigger market volatility. The report also serves as a critical benchmark for Social Security adjustments during the unprecedented data gap.
What This Means for You:
- Expect heightened S&P 500 volatility if CPI exceeds 0.4% monthly – consider tightening stop-loss orders on growth stocks
- Monitor core CPI subcategories (especially autos and import-heavy goods) for tariff passthrough effects on your supply chain costs
- Position portfolios for Fed rate cut probability shifts – 10-year Treasury yields may swing 10-15 basis points on report surprises
- Prepare contingency pricing models for Q4 given unreliable inflation inputs until government operations resume
Original Post:
A shopper looks at produce at a grocery store in West Milton, Ohio, US, on Tuesday, Oct. 21, 2025.
Kyle Grillot | Bloomberg | Getty Images
The Friday release of September’s consumer price index report is pretty much the only game in town this month for a Wall Street that is hungry for data, raising the chances for it to be a market-moving event.
While the actual numbers are expecting to land about where they’ve been in recent months, the dearth of official economic reports, thanks to the government shutdown, means even a slight deviation could cause an outsized impact.
“Because we haven’t gotten any government data in the recent past, I think all of the market’s focus and all of the market’s attention is going to be directed onto this one report,” said Troy Ludtka, senior U.S. economist at SMBC Nikko Securities. “This is going to be the report to end all reports.”
As far as the Wall Street consensus goes, though, the CPI release from the Bureau of Labor Statistics looks to be more of the same.
Economists surveyed by Dow Jones expect the monthly all-items reading to increase by 0.4%, the same as a month ago, putting the 12-month inflation rate at 3.1%, or 0.2 percentage point higher than the August level. Excluding food and energy, core CPI is projected to show a 0.3% monthly increase and a 3.1% annual level, both the same as in August. The yearly rate would be the highest since January.
What the Street will be looking for is any deviation in the readings showing that inflation is running hotter or colder than anticipated. The focus also will be on the details showing what impact President Donald Trump’s tariffs are having on prices.
The report, which was supposed to be released Oct. 15, will be the last significant economic reading before the Fed’s policy meeting that concludes Wednesday. The BLS called workers back because it uses CPI as a benchmark for Social Security cost of living adjustments.
Lack of clarity
Goldman Sachs economists expect little change on auto prices, a boost on car insurance and a decline in airfare. On the tariff issue, the firm said in a note that it expects “upward pressure” on categories such as communication, household furnishings and recreation, but an addition of just 0.07 percentage point to the core inflation figure.
However, data in general is a black box with so much of the government shut down, raising some questions over the reliability of the CPI.
“We don’t have full clear clarity with the lack of important data points that the market depends on due to the government shutdown,” said Vishal Khanduja, head of broad markets fixed income at Morgan Stanley Investment Management. “So that adds to the uncertainty a little bit more.”
Indeed, investors have been on tenterhooks lately, pushing major stock market averages to around record territory despite continued fluctuation in day-to-day moves.
Geopolitical uncertainty is at the root of concerns, with the ever-shifting tariff landscape injecting worry that higher prices could slow what has been an otherwise surprisingly strong pace of economic growth. The CPI report, despite concerns about how clean the data will be due to shutdown-related disruptions, should help answer at least some of those questions.
That applies both to markets and the Federal Reserve, which holds a policy meeting next week at which officials are widely expected to approve another quarter percentage point interest rate cut.
“In terms of market impact, it would take a meaningful surprise to the upside for the market to change its mind about an additional interest rate cut,” said Julien Lafargue, chief market strategist at Barclays Private Bank.
Outside of the trade war’s frequent gyrations, markets have been boosted by another strong earnings season. Prior to the lockdown, economic data also had shown a surprisingly resilient economy, with gross domestic product tracking close to 4% for the third quarter, according to the Atlanta Fed.
While it would take something of consequent to shake that narrative, a surprise from CPI might just be the ticket.
“I would expect volatility if the number comes in higher than expected,” said Stephanie Link, chief investment strategist at Hightower Advisors. “I would view that as a buying opportunity as the economy is strong, the Fed is beginning a cutting cycle, EPS are growing double digits and the fourth quarter is seasonally the strongest quarter of the year.”
Extra Information:
• Government Shutdown Impact on Monetary Policy – Details how data gaps complicate Fed decision-making
• Atlanta Fed GDPNow Tracker – Real-time GDP estimates absent official reports
• August CPI Benchmark Data – Crucial comparison for September’s report analysis
People Also Ask About:
- Why does CPI matter for stock investors? – CPI directly influences Fed rate decisions which affect equity valuations.
- How reliable is CPI during government shutdowns? – Data collection methodology remains intact but auxiliary economic indicators are missing.
- What’s the difference between headline and core CPI? – Core CPI excludes volatile food/energy prices, better showing underlying trends.
- How quickly do tariffs affect consumer prices? – Passthrough effects typically appear within 3-6 months for affected goods.
Expert Opinion:
“This unprecedented data vacuum magnifies CPI’s importance beyond its typical weight,” notes former BLS Commissioner Erica Groshen. “Market participants should particularly scrutinize the shelter component – constituting one-third of CPI – as real-time private rental data suggests possible deceleration not yet reflected in government figures.”
Key Terms:
- Inflationary pressure indicators during government shutdown
- CPI data analysis amidst budget impasse
- Federal Reserve interest rate decisions 2025
- U.S. tariff policy impact on consumer prices
- Core inflation vs headline CPI metrics
- Market volatility triggers from economic reports
- BLS data collection protocols during furloughs
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