What is the Consumer Price Index?

The Consumer Price Index for All Urban Consumers (CPI-U) is the most widely followed measure of inflation in the United States. Published monthly by the BLS, it tracks changes in the prices paid by urban consumers for a market basket of goods and services covering approximately 93% of the US population. The basket includes categories such as housing, food, transport, energy, medical care, apparel, and recreation, with housing carrying the largest weighting at around 32%.

The BLS collects price data from tens of thousands of retail and service establishments. The index is expressed as the year-over-year (YoY) rate and the month-over-month (MoM) change. Core CPI, excluding food and energy, is the metric most closely watched by the Federal Reserve (the Fed) for underlying inflation trends.

CPI is released roughly 12 to 13 days after the reference month ends. The December 2026 release covers price changes in November 2026 and will contribute to the full-year inflation picture for 2026.

US CPI Release: December 10, 2026

The December 10 release will provide the November 2026 inflation reading, arriving one day after the FOMC meets on December 9. While the data will not influence the December rate decision directly (the Fed will already have made its call), it will immediately shape market expectations for the path of monetary policy in 2027. Strong inflationary persistence would push back the anticipated timeline for rate cuts; a confirmed deceleration would accelerate them.

US inflation started 2026 at 2.4% year-over-year in January before surging to 3.8% in April, the highest rate since May 2023, according to BLS data. The energy component rose 17.9% year-over-year in April, with gasoline prices up 28.4%. The December reading will reveal whether those energy-driven price rises have faded through favourable base effects or have entrenched into broader price pressures. Consensus forecasts will be available closer to the release date.

Why This CPI Release Matters

The December CPI is the last major inflation data point of 2026 and will set the inflation narrative going into 2027. It follows the FOMC decision by just one day, meaning the December 10 release will immediately begin shaping expectations for the January and March 2027 meetings. If the Fed cuts in December, a hot November CPI reading could cause markets to question whether that cut was premature. If the Fed holds, a cool reading would reinforce expectations for early 2027 easing.

At the same time, the December reading will set the base for year-over-year comparisons in early 2027. If November 2026 inflation is significantly lower than November 2025, the year-over-year rate will reflect that mechanically. Understanding the base effect is essential for interpreting the early 2027 inflation prints that follow.

For bond markets, the December release will be crucial in determining where longer-duration yields settle into year-end and the new year. For equities, confirmation that the 2026 inflationary episode is behind us would be a material positive, particularly for rate-sensitive growth stocks that have faced persistent valuation headwinds throughout the year.

What to Watch For

• Above consensus: A reading that shows inflation re-accelerating in November (above 3.0-3.5%) would be a negative surprise given that energy base effects should be fading by this point. It would signal structural inflation persistence and push out expectations of rate cuts in 2027, weighing on equities and bonds.
• In line with consensus: A reading matching expectations would confirm the trajectory already priced in by markets. Attention would quickly shift to the December FOMC press conference and forward guidance for 2027, particularly the updated Summary of Economic Projections.
• Below consensus: A reading below 2.5% would signal that the 2026 inflation surge has been largely unwound and would significantly increase expectations of rate cuts early in 2027. Equities would rally broadly, bond yields would fall, and the US dollar would weaken.

By December, the base effect from the April 2026 energy spike will be highly relevant. If energy prices have normalised or fallen since mid-2026, the November year-over-year comparison will benefit from a mechanically easier base. Core services and shelter inflation will be the genuine gauge of underlying price pressure divorced from energy volatility.

Historical Context

Source: US Bureau of Labor Statistics. October and November 2025 data were not published due to the US government shutdown. MoM and core figures not available for all periods shown.

Market Positioning

The December 2026 CPI will close out the year’s inflation story and establish the baseline for 2027 expectations. Fixed income markets and the Fed funds futures curve will be acutely sensitive to this final reading, given that it arrives the day after the December FOMC decision and in the context of year-end portfolio rebalancing. Liquidity typically thins in mid-December, which can amplify market movements around data releases.

For equity investors looking ahead to 2027, a confirmed downward trend in inflation through the final quarter of 2026 would represent a material improvement in the macro backdrop, reducing the headwind from high interest rates and potentially re-opening the door to multiple expansion in growth sectors.

Related Events

• US CPI Report November 2026 – The preceding monthly release covering October 2026 data.
• FOMC Rate Decision December 2026 – The Fed’s final meeting of 2026 on December 9, the day before this CPI release.
• ECB Rate Decision December 2026 – The ECB’s December meeting on December 17, providing a comparison with European monetary policy as the year closes.

Frequently Asked Questions

What does the CPI measure?

The CPI measures the average change in prices paid by urban consumers for a fixed basket of goods and services, including housing, food, transport, energy, and medical care. Published monthly by the Bureau of Labor Statistics, it is the primary measure of consumer price inflation in the United States.

When is the December 2026 CPI report released?

The December 2026 CPI report will be released on Thursday, December 10, 2026, at 8:30 a.m. Eastern Time. The report covers price changes during November 2026.

How does the December CPI relate to 2027 monetary policy?

The December 10 release follows the FOMC’s December 9 decision by one day, meaning it will not affect December’s vote but will immediately recalibrate expectations for January and March 2027 meetings. A continued deceleration in inflation would strengthen the case for the Fed to begin or continue cutting rates early in 2027, which would have significant implications for bond yields, equity valuations, and the US dollar.