What is CPI?
The Consumer Price Index tracks the prices of a large basket of goods and services bought by urban households — food, energy, housing, transport, medical care, clothing, recreation and more. BLS weights each item by its share of household spending and combines the prices into a single index.
Markets focus mostly on the month-over-month change (m/m) — the figure NEXTMarketReaction uses — and also watch the year-over-year change (y/y).
Why markets pay attention
Keeping inflation under control is one of the Federal Reserve's core goals. When prices rise faster than expected, the Fed may keep interest rates higher for longer, or raise them; when inflation cools, the case for lower rates grows.
Rising prices shrink what the same income can buy, so persistent inflation erodes households' purchasing power. That is why an inflation surprise can quickly change expectations for U.S. interest rates — and, with them, for the dollar.
CPI and related releases
Core CPI comes out in the same release and leaves out food and energy, whose prices swing a lot. Markets often treat core as the cleaner signal of underlying inflation, so a headline surprise driven only by energy may matter less than one that core confirms.
The Producer Price Index (PPI) measures the prices producers receive. It can hint at cost pressure that may later reach consumers, but the link is not direct.
Actual, Forecast and Previous
Every release on an economic calendar comes with three numbers:
- Actual
- The result just published. Nobody knows it until the release.
- Forecast
- The consensus of economists, known in advance — what the market largely expects and has already priced in.
- Previous
- The result for the prior period (sometimes revised). Useful context, but not what markets mainly react to.
Surprise = Actual − Forecast
The key point: markets react mainly to how far the Actual lands from the Forecast — the surprise — not to the change from the Previous value.
Actual > Forecast
Higher than expected.
Actual ≈ Forecast
About as expected — usually the smallest reaction.
Actual < Forecast
Lower than expected.
None of these comparisons decides the EUR/USD direction on its own. Whether "higher" is good or bad news depends on the indicator (more jobs usually reads as strength, more jobless claims as weakness), on the size of the surprise and on the market context.
How a CPI surprise is usually read
An Actual above the Forecast (hotter inflation) raises the odds of tighter Fed policy. Historically, that has more often supported the U.S. dollar — for EUR/USD, usually a move lower. An Actual below the Forecast (cooler inflation) has more often had the opposite effect.
CPI m/m is usually published to one decimal place (for example 0.3%), so even a 0.1 percentage-point surprise can matter. How much it matters depends on what the market already expects from the Fed.
A simple example
Hypothetical numbers: Previous 0.2%, Forecast 0.3%, Actual 0.5%. The surprise is +0.2 percentage points — prices rose faster than expected.
If Core CPI in the same release matched its Forecast, the market may conclude that the jump came from volatile energy prices, and the reaction may be smaller or fade. If Core CPI also came in above expectations, the inflation message is broader and harder to dismiss.
Why the same number can move markets differently
The size of the surprise matters
A result slightly off the Forecast may barely register, while a big miss can force a real rethink. Larger surprises have tended to produce larger and more consistent reactions — but not always.
Context changes over time
When inflation is the market's main worry, inflation data dominates; when growth is the worry, jobs and activity data can matter more. What the market already expects from the Federal Reserve also shapes how a surprise is read.
Details and revisions
Headlines come with details — revisions to earlier months, sub-components, other figures released at the same moment. They can confirm the headline or contradict it.
The first reaction is not the final one
The first move reflects the headline in the first seconds. As participants read the details, the market can extend that move, stall or reverse within minutes.
History is a guide, not a guarantee
Past releases show how markets have tended to react, which is useful. But every release happens in a new context, and past behavior does not guarantee the next reaction.
How to read EUR/USD
EUR/USD shows how many U.S. dollars one euro buys, so it tends to move opposite to the dollar: when the dollar strengthens, EUR/USD usually falls, and when it weakens, EUR/USD usually rises. Pairs where the dollar comes first, such as USD/JPY, tend to move with the dollar.
How NEXTMarketReaction reads this release
When a Consumer Price Index (CPI) release is published, NEXTMarketReaction combines:
- the Actual, as soon as it is published;
- the Forecast (consensus) and the Previous value;
- the surprise — how far, and in which direction, the Actual landed from the Forecast;
- how EUR/USD has behaved after comparable Consumer Price Index (CPI) releases in the past;
- calibrated historical probabilities, adjusted so that the percentages reflect how often similar situations actually played out;
- the horizon: 1, 3, 5, 8 or 15 minutes after the release.
The UP/DOWN percentage you see is a probability estimate based on history and a statistical model — not a certainty and not a recommendation. Even a high percentage leaves the opposite outcome possible.