US Macro

Consumer Price Index, Year-over-Year

CPI year-over-year measures the percent change in a basket of consumer goods and services from twelve months earlier. It's the most-quoted inflation gauge in the United States — the single number that drives Federal Reserve policy debates, Social Security cost-of-living adjustments, real wage negotiations, and the pricing of every Treasury bond.

May 13, 2026CPIAUCSLinflation · fed-policy · us-macro · real-returns

CPI_YOY

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There's no economic indicator that touches more people more directly. CPI year-over-year sets the cost-of-living adjustment that determines what 67 million Americans receive in monthly Social Security checks. It anchors the discount rate the Treasury pays on inflation-protected bonds. It frames every Federal Reserve press conference, every union contract negotiation, every retiree's lived experience of whether last year's savings will buy this year's groceries. The 2021–2024 cycle was a forty-year stress test of the entire post-Volcker monetary regime.

CPI_YOY

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What it measures

CPI year-over-year is a simple percent change:

The underlying index — published as CPIAUCSL by the Bureau of Labor Statistics and republished by FRED — is the Consumer Price Index for All Urban Consumers, US City Average, seasonally adjusted, indexed to a base of 100 over the 1982–1984 period. It is a monthly release, typically the second week of the following month.

The basket comes from the Consumer Expenditure Survey: roughly 80,000 prices collected each month across 75 urban areas and 23,000 retail outlets, weighted by spending shares from a rolling two-year window. The largest single weight is shelter at ~35%, followed by transportation (~17%), food (~13%), and medical care (~8%).

Why it matters

Two angles, one macro and one micro.

The policy angle. The Federal Reserve's mandate is "price stability," which it has operationally defined as 2% inflation — measured in core PCE, but with CPI as the most-watched real-time proxy. Real interest rates are nominal rates minus inflation, so CPI YoY directly determines whether a 5% Treasury yield is generous (when inflation is 2%) or punishing (when inflation is 7%). The TIPS market — roughly $2 trillion in inflation-protected Treasuries — uses headline CPI to compute principal adjustments. Every quarterly earnings call from an inflation-sensitive business (retail, restaurants, healthcare) anchors its commentary to where CPI is and where it's heading.

The everyday angle. Social Security COLAs are set each October based on CPI-W (a slight variant of CPI-U) from the prior third quarter — a single reading sets what retirees receive for the next twelve months. Wage negotiations in unionized industries — autos, airlines, longshoremen — often include explicit CPI-tied escalators. Federal income tax brackets, the standard deduction, the maximum 401(k) contribution, and the alternative minimum thresholds are all indexed to chained CPI. Mortgage refinancing decisions, asset allocation between cash and equities, the calculus of whether to lock in a multi-year contract — all of these change shape when CPI is 2% versus when it is 8%.

What moves it, and what it moves

Moves CPI:

Money supply and aggregate demand. Wage growth (Atlanta Fed Wage Growth Tracker, ECI), M2 expansion, household savings deployment, fiscal stimulus checks. The 2021 surge had a meaningful demand-pull component: pandemic savings collided with reopening.
Commodity prices. Crude oil flows through to gasoline and shipping costs within weeks; natural gas through to heating and electricity within months; agricultural commodities through to food prices over a season.
Housing market. Asking rents and home prices feed into Owners' Equivalent Rent with a 12-18 month lag. This is the slowest-moving and most persistent CPI component, and the one that explains most of the "stickiness" of inflation after a shock.
The US dollar. A strong DXY makes imports cheaper, which pulls headline CPI down (the US is a net importer of consumer goods). A weak DXY does the opposite.
Supply-side conditions. Shipping rates, semiconductor inventories, port congestion, tariffs and trade policy. The 2021-2022 surge had a large supply-shock component layered on top of the demand-side one.

CPI moves:

Federal Reserve policy — rate decisions, balance sheet posture, forward guidance.
Real interest rates, and therefore Treasury yields, mortgage rates, and corporate borrowing costs across the curve.
TIPS pricing and 10-year breakeven inflation (10y nominal minus 10y TIPS).
Social Security benefit levels and federal tax bracket thresholds.
Wage demands in unionized industries and bargaining-table real-wage calculations.
Equity sector rotation — financials, energy, and consumer staples behave very differently under high-inflation regimes than tech and consumer discretionary.

A worked example: the 2021–2024 inflation cycle

The pre-pandemic decade had been a story of remarkable price stability. From 2012 through 2019, CPI YoY averaged 1.8% and never crossed 4%. Inflation, as an economic problem, felt solved.

That ended in March 2021. CPI YoY hit 2.6%, then 4.2% in April, then 5.0% in May. The Fed and Treasury initially characterized this as "transitory" — a story about base effects, supply-chain bottlenecks, and one-time reopening demand. By October 2021, headline CPI was at 6.2%, and the transitory framing was visibly breaking down.

The Fed began hiking in March 2022 with a 25-basis-point move, immediately followed by a 50bp move in May and four consecutive 75bp moves through fall 2022 — the fastest tightening cycle since Volcker. CPI YoY peaked at 9.1% in June 2022 — a forty-year high. The fed funds rate ended 2022 at 4.25–4.50%, having started the year at 0.00–0.25%.

By mid-2023 the federal funds rate had reached its terminal range of 5.25–5.50%, and CPI YoY had retreated to roughly 3%. Through the second half of 2023 and most of 2024, inflation ground lower — slower than the Fed hoped, but consistently downward. The Fed delivered its first cut, a jumbo 50bp move, in September 2024, with CPI YoY at approximately 2.5%.

The 525-basis-point hiking cycle from March 2022 to July 2023 brought inflation from 9.1% to below 3% without producing the recession most macro models had forecast. That outcome — the rare "soft landing" — is now one of the most discussed monetary policy results of the post-war era, and the proximate reason both the 2s10s yield curve inversion and the Sahm Rule unemployment signal failed to produce their usual recessionary follow-through.

The current cycle, and the open question

The open question now is where CPI settles. Three positions are in active circulation:

Back to 2% (Fed orthodoxy) — the disinflation will continue as housing finally rolls over in OER and labor markets soften. Pre-COVID norms reassert.
A new 3–3.5% plateau (the "regime change" view) — de-globalization, demographic tightening, ongoing fiscal deficits, and the cost of energy transition make 2% structurally unattainable. The Fed eventually tolerates this either explicitly (target revision) or implicitly (mission drift).
Re-acceleration risk (the contrarian view) — if labor markets stay tight, immigration policy tightens, or a commodity shock arrives, the 2024 disinflation reverses and the Fed is forced back into hiking with a credibility problem.

What you watch for: shelter inflation finally returning to its pre-COVID 3% pace (it's been sticky at 4-5% well past where market rents implied it should be); ECI / Atlanta Fed wage growth tracker rolling toward 3% (3% wage growth + ~1% productivity = roughly 2% unit labor cost growth, which is the Fed's preferred underlying-inflation indicator); long-term inflation expectations from the U-Mich and NY Fed surveys staying anchored near 3%.

FAQ

Why does the Fed prefer PCE over CPI as its inflation gauge?

The Fed's official 2% inflation target is denominated in core PCE (Personal Consumption Expenditures), not CPI. PCE has a broader scope (it includes all consumer spending, not just out-of-pocket household expenses — e.g., employer-paid health insurance), a chain-weighted basket that updates more quickly to reflect substitution behavior, and tends to run 30-50 basis points lower than CPI on average. CPI is still the more widely watched number publicly because it has a longer history, monthly release, and direct legal use in Social Security and TIPS calculations.

Why does 'core' CPI exclude food and energy?

Food and energy prices are volatile in ways that don't reflect underlying inflation pressures — a hurricane in the Gulf can spike gasoline prices for a few weeks; a frost in Florida can spike orange juice prices for a season. The Fed (and most economists) care about the persistent, demand-driven component of inflation, which is harder to read when these volatile categories are bouncing around. Core CPI strips them out to make the underlying trend visible. The trade-off is that food and energy are roughly 20% of household spending, so 'core' is an analytical tool, not a description of what people actually buy.

How is 'shelter' calculated, and why is it controversial?

Shelter is roughly 35% of the CPI basket — by far the largest single component. For renters, the BLS uses actual rent paid. For homeowners, it uses 'Owners' Equivalent Rent' (OER) — what the homeowner would pay to rent their own house. OER is estimated by surveying nearby comparable rentals. The controversy is that OER lags actual housing-market conditions by 12-18 months because lease contracts are sticky, so when housing prices and market rents are turning, CPI under-reports inflation on the way up and over-reports on the way down. The post-2022 disinflation has been particularly affected: market rents peaked in mid-2022, but OER didn't peak in CPI until mid-2023.

What's the difference between headline and core CPI?

Headline CPI is the full basket; core CPI excludes food and energy. The FRED series for headline is CPIAUCSL; for core, it's CPILFESL. The two can diverge sharply in the short run — e.g., during the 2022 oil price spike, headline ran 1-2 percentage points above core; during the 2014-2015 oil collapse, headline ran below core. Over horizons longer than a year or two, they converge: food and energy mean-revert, and the persistent inflation pressure that matters for monetary policy shows up in both.

How quickly does CPI respond to Federal Reserve rate changes?

Famously slowly. The standard estimate from VAR studies is that monetary policy affects inflation with a lag of 12-18 months for the bulk of its effect, with the tail extending out to 24 months or more. The 2022-2023 hiking cycle is a real-world demonstration: the Fed started raising rates in March 2022, but headline CPI didn't roll over until July 2022 and didn't return to 3% until mid-2024 — roughly a 24-month full transmission. This lag is the central challenge of monetary policy: by the time the Fed sees what its decisions did to inflation, it's already been 12+ months since the decision.