Core CPI
Core CPI is a measure of inflation that tracks changes in consumer prices for all goods and services except food and energy, which the Bureau of Labor Statistics publishes monthly.
The Consumer Price Index for All Urban Consumers (CPI-U) is the broadest measure of retail inflation in the United States, but policymakers and economists often focus on the 'core' version, which strips out the food and energy components. The rationale is that food and energy prices are subject to large, temporary swings driven by weather, geopolitical shocks, and commodity markets that can obscure the underlying inflation trend. Core CPI is intended to reveal the more persistent inflation pressures building in an economy.
The Bureau of Labor Statistics (BLS) releases the CPI report monthly, typically in the second week of the month covering the prior month's data. The index is constructed by tracking the prices of a representative basket of goods and services purchased by urban consumers, including shelter, medical care, education, apparel, and transportation. Core CPI excludes roughly 19% of the overall basket (food and energy). Changes are expressed as year-over-year and month-over-month percentages.
Shelter costs — primarily owners' equivalent rent and rent of primary residence — carry the heaviest weight in core CPI, representing approximately 40% of the core index. Because rents adjust slowly through long-term lease cycles, shelter inflation tends to lag changes in the broader housing market by twelve to eighteen months, which is an important consideration when interpreting core CPI readings.
The Federal Reserve uses core CPI as one input — alongside the core PCE Price Index — when assessing whether inflation is running above or below its 2% target. When core CPI prints consistently above 2% on a year-over-year basis, the Fed typically views that as justification for tighter monetary policy. When it falls below 2% for extended periods, accommodative policy may follow.
For market participants, the monthly CPI release is one of the most closely watched economic reports. A hotter-than-expected core CPI reading tends to push Treasury yields higher, strengthen the U.S. dollar, and weigh on equity valuations, particularly for growth stocks whose future earnings are discounted at a higher rate.