Why Inflation Numbers Move Stock Prices

Inflation numbers move stock prices mainly because they change what investors expect the Federal Reserve to do with interest rates, and those expectations feed into the rates used to value future profits. A higher-than-expected reading usually lifts short-term Treasury yields on the day of the 8:30 a.m. Eastern release. In 2022 stocks usually fell when that happened, but since 2023 the same-day link has been weak. Inflation also reaches share prices more slowly, through company costs and pricing power and through the lower valuations that have historically gone with high inflation.

Key takeaways

The monthly Consumer Price Index (CPI) report is the first broad reading of consumer prices each month; the Fed's 2% goal is defined on a different index, the PCE price index, which comes out later.
In 2022, the S&P 500 moved 1.93% on an average CPI release day against 1.16% on other days; from 2024 to September 2026 the gap shrank to 0.74% against 0.65%.
The February 2023 CPI report (6.0% a year) came out on March 14, 2023, during a banking crisis; the S&P 500 rose 1.65% that day.
Because October 2025 prices were never collected, BLS will not publish 12-month changes for October 2026 for most indexes in the report due November 10, 2026.

What the CPI report measures

The Bureau of Labor Statistics (BLS) describes the CPI as a measure of the average change over time in the prices paid by consumers for a basket of goods and services. The headline series, CPI-U, covers urban consumers, over 90% of the US population. "Core" CPI is the index for all items less food and energy, which swing more than the rest.

The report comes out an hour before the stock market opens. The September 2026 report, released on October 14, 2026, showed prices up 0.6% for the month (seasonally adjusted) and 3.7% over 12 months, with core up 0.3% and 2.6%.

Why shelter carries so much weight

According to the BLS fact sheet on rent and owners' equivalent rent, shelter's relative importance was 35.625% of the CPI as of December 2025. Owners' equivalent rent (OER) of primary residences, an estimate of what homeowners would pay to rent their own homes, was 25.230%, and rent of primary residence was 7.840%. OER's price change is measured from a sample of rental units, not from house prices.

The 2025 gap in the data

A lapse in federal appropriations stopped CPI price collection for October 2025. BLS canceled the October 2025 release and moved November's report to December 18, 2025. The December 18, 2025 release said BLS was unable to collect the October data retroactively, so it reported two-month changes instead: 0.2% for all items and 0.2% for core from September to November.

The effects carry into 2026. BLS's shutdown FAQ (updated September 16, 2026) says October 2025 prices were carried forward from September and rents from April 2025, leaving the rent and OER indexes unchanged that month. It also says BLS will not publish 12-month percent changes for October 2026 for indexes where October 2025 data are unavailable, which covers most CPI series.

CPI, PCE and PPI side by side

Report	Publisher	What it measures	Latest reading checked
Consumer Price Index (CPI-U)	BLS	Out-of-pocket prices paid by urban households; modified Laspeyres formula	Sept 2026: +3.7% over 12 months; core +2.6%
PCE price index	Bureau of Economic Analysis (BEA)	Prices of spending by and on behalf of households, including spending by nonprofits serving households; Fisher-Ideal formula	Aug 2026: +3.4% over 12 months; core +3.0%

The Fed's Statement on Longer-Run Goals and Monetary Policy Strategy (adopted 2012, amended August 22, 2025) defines its target as inflation of 2 percent "as measured by the annual change in the price index for personal consumption expenditures." BEA's FAQ on CPI and PCE differences groups the gaps into a formula effect, a weight effect, a scope effect and other effects such as seasonal adjustment. The gap can be large: in August 2026, core PCE rose 3.0% over 12 months, while the August 2026 CPI report put core CPI at 2.4%.

CPI still tends to get the market's first reaction because it arrives earlier: August 2026 CPI came out on September 11, and August PCE on September 30. The BLS Producer Price Index (PPI), sometimes released a day before the CPI, measures selling prices received by domestic producers, a read on cost pressure that may or may not reach consumers.

Monthly versus yearly readings

The 12-month rate in the headlines comes from unadjusted data, while the one-month change is seasonally adjusted. The 12-month rate depends on the month dropping out a year back as well as on the month just added, a base effect.

(1 + YoY_t) = (1 + YoY_t-1) × (1 + m_t) ÷ (1 + m_t-12)

YoY_t    = 12-month change for the current month
YoY_t-1  = 12-month change for the previous month
m_t      = unadjusted one-month change in the current month
m_t-12   = unadjusted one-month change in the same month a year earlier

A worked example from the unadjusted CPI-U (CPIAUCNS on FRED): the 12-month rate was 4.05% in May 2023. In June 2023 the index rose 0.32% (unadjusted), but the month dropping out, June 2022, had risen 1.37%. So 1.0405 × 1.0032 ÷ 1.0137 = 1.0297, a 12-month rate of 2.97%. The yearly rate fell by more than a full point in one month even though prices kept rising.

Monthly figures are often annualized as a rough check against the 2% goal, which is defined on the PCE index, not the CPI. Illustrative example: a 0.3% monthly rise compounds to 1.003 raised to the 12th power, minus 1, or about 3.7% a year; 0.2% compounds to about 2.4%. A one-tenth difference in monthly core is more than a full point at an annual rate.

Four channels to stock prices

Prices react to the part of a release that differs from what investors already expected, not to the level of inflation by itself. From there, an inflation number reaches stocks along four routes.

1. The expected path of Fed policy

A hot reading raises the odds of higher policy rates or fewer cuts. The 2-year Treasury yield reflects expected policy over roughly two years, so it shows the reaction clearly. Computed from FRED's 2-year Treasury yield (DGS2) and S&P 500 (SP500) series, the 2-year yield moved by 13.7 basis points (hundredths of a percentage point) on an average 2022 CPI day, in either direction, against 5.7 on other days; from 2023 to September 2026 the figures were 7.0 and 4.7. In 2022 stocks and the 2-year yield moved in opposite directions on 9 of 12 release days, a correlation of −0.67; from 2023 to September 2026 that happened on 24 of 44 days, a correlation of −0.16.

2. Discount rates and real yields

Stock prices are claims on profits years ahead, so they are sensitive to the real (inflation-adjusted) rates used to discount them. During 2022 the 10-year Treasury inflation-indexed yield (DFII10) rose from −1.04% at the end of 2021 to 1.58% at the end of 2022, and the 2-year yield from 0.73% to 4.41%. The S&P 500 price index fell 19.4% over the same period, from 4,766.18 to 3,839.50, the direction the mechanism predicts: higher real discount rates lower the present value of distant profits. The effect holds only if nothing else changes: by the end of 2024 the real yield had risen further, to 2.24%, while the S&P 500 had gained 53% from its 2022 close, as earnings growth and other forces outweighed it.

3. Profit margins and pricing power

Inflation raises companies' costs and, for some, their prices; margins depend on which moves faster. Kansas City Fed research (Glover, Mustre-del-Río and von Ende-Becker, 2023) estimated that markups rose 3.4% during 2021 while PCE inflation was 5.8%, and found the pattern more consistent with firms raising prices ahead of expected cost increases than with greater monopoly power.

4. Valuation multiples

High inflation has historically gone with lower price-to-earnings ratios. Modigliani and Cohn (1979) proposed that investors suffer "inflation illusion," discounting real cash flows at nominal interest rates. A San Francisco Fed Economic Letter (2004-30) noted that the market P/E stayed below its long-run average for more than a decade in the high-inflation late 1970s and early 1980s. Campbell and Vuolteenaho (NBER, 2004) found that the level of inflation explained almost 80% of the variation in their measure of stock-market mispricing. A Fed Board paper by Steven Sharpe traced the link to lower expected real earnings growth and higher required real returns: a one-point rise in expected inflation raised required real returns by about one point, implying on average a 20% lower stock price level. These are historical estimates, not rules.

Why sectors react differently

The same report can lift some industries and hit others. Boudoukh, Richardson and Whitelaw (Journal of Finance, 1994) found that stock returns in noncyclical industries tended to move positively with expected inflation, while cyclical industries showed the opposite relation, which they tied to how each industry's output moves over the business cycle. Firms whose value rests on profits far in the future are more exposed to the discount-rate channel.

CPI release days, 2022–2026

The table sets first-published BLS figures (checked against ALFRED vintages) against close-to-close S&P 500 moves and daily 2-year yield changes from FRED.

Release date	Data month	Headline CPI, 12 months	Core CPI, 1 month	2-year yield	S&P 500
Fri, Jun 10, 2022	May 2022	8.6%	0.6%	+23 bp	−2.91%
Wed, Aug 10, 2022	Jul 2022	8.5%	0.3%	−5 bp	+2.13%
Tue, Sep 13, 2022	Aug 2022	8.3%	0.6%	+17 bp	−4.32%
Thu, Nov 10, 2022	Oct 2022	7.7%	0.3%	−27 bp	+5.54%
Tue, Mar 14, 2023	Feb 2023	6.0%	0.5%	+17 bp	+1.65%
Tue, Nov 14, 2023	Oct 2023	3.2%	0.2%	−22 bp	+1.91%
Wed, Apr 10, 2024	Mar 2024	3.5%	0.4%	+23 bp	−0.95%
Thu, Dec 18, 2025	Nov 2025	2.7%	0.2% over 2 months	−3 bp	+0.79%
Wed, Jun 10, 2026	May 2026	4.2%	0.2%	0 bp	−1.62%
Fri, Sep 11, 2026	Aug 2026	3.4%	0.3%	+7 bp	+0.86%

Two 2022 days show the policy channel clearly. The June 10, 2022 report showed 8.6% inflation, which BLS called the largest 12-month increase since December 1981; the 2-year yield rose 23 basis points and the S&P 500 fell 2.91%, then another 3.88% on the next trading day. On September 13, 2022, a 0.6% rise in core outweighed a soft headline figure, and the index fell 4.32%.

What happened on March 14, 2023

The February 2023 CPI report, released March 14, 2023, showed prices up 0.4% for the month and 6.0% over 12 months, with core up 0.5% and shelter accounting for over 70% of the monthly increase. The S&P 500 did not drop that day: it closed 1.65% higher, at 3,919.29, and after a 0.70% fall on March 15 was still 0.94% above the March 13 close. It landed two days after a joint statement by Treasury, the Fed and the FDIC on the failures of Silicon Valley Bank and Signature Bank. The 2-year yield had dropped from 5.05% on March 8 to 4.03% on March 13 before rising 17 basis points, so the day's moves reflected the banking news as much as the inflation figure.

Limits of a one-day table

Release days were more volatile than other days only in some periods. The S&P 500's average absolute move on CPI days was 1.93% in 2022 against 1.16% on other days, 0.62% against 0.65% in 2023, and 0.74% against 0.65% from 2024 to September 2026. A one-day change also mixes in other news, and the table omits the consensus forecasts that define a surprise.

Frequently asked questions

Does the CPI include house prices or mortgage payments?

No. BLS treats buying or improving a home as investment, and its fact sheet says mortgage interest, property taxes and real estate fees are not consumption items either. Homeowners' costs enter the CPI through owners' equivalent rent, priced from rental units.

Can a CPI figure change after markets have reacted?

The unadjusted indexes are final when issued, according to BLS. Seasonally adjusted figures can change: BLS re-estimates seasonal factors each year and revises the previous five years of seasonally adjusted data, so a monthly change that moved markets can later be shown slightly higher or lower.

How precise is a single monthly CPI change?

The CPI is built from samples, so it carries sampling error. The September 2026 release gives a standard error of 0.04 percentage point for the one-month change in all items, with prices collected in 75 urban areas from about 6,000 housing units and about 22,000 retail establishments.

Why can headline and core CPI point different ways?

Headline includes food and energy, and energy prices can swing sharply in a single month. In August 2022, the headline index rose 0.1% while core rose 0.6%, because the gasoline index fell 10.6% and offset broad increases in shelter, food and medical care. Core removes those items to show the underlying trend, but households still pay headline prices.

Does a hot CPI report always push stocks lower?

No. The October 13, 2022 report showed core prices up 0.6% for the month and 8.2% headline inflation over 12 months, and the 2-year yield rose 19 basis points that day. The S&P 500 still closed 2.60% higher, then fell 2.37% the next trading day.

Reading the next CPI release

Check the date on the BLS release schedule: October 2026 data are due November 10, 2026, and November data December 10, 2026, both at 8:30 a.m. Eastern.
Read the seasonally adjusted one-month core change first; annualized, it is only a rough guide to the 2% goal, which is set on the PCE index released after the CPI.
Before reading a change in the 12-month rate as a trend, compare the current month's change with the month dropping out a year earlier.
Look at the shelter and energy lines, which often explain the gap between headline and core.
Watch the 2-year yield for the market's policy reading; treat same-day stock moves as a mix of the report and other news.