How to Trade CPI Inflation in Forex
How to trade CPI inflation in forex starts with one fact: a currency moves on the gap between the reported figure and the forecast, not on the figure itself. The report changes what traders expect the central bank to do next, and that expectation moves the price.
What the index measures is in What Is CPI (Consumer Price Index)? This article is about reading the release. None of it tells you which way a currency will move, or promises a result.
Why inflation moves a currency
A central bank raises interest rates when inflation runs above its target and lowers them when it runs below. Higher expected rates tend to draw money to a currency.
Which inflation number counts differs by central bank:
- The European Central Bank aims for 2% over the medium term, measured by the HICP (ECB).
- The Bank of England has a 2% target on CPI, set by the UK government (Bank of England).
- The Federal Reserve sets its 2% goal on the PCE price index, not on CPI (Federal Reserve FAQ). Stable prices are half of its job; maximum employment is the other half (the dual mandate).
US CPI still matters, because it is one of the first monthly reads on how close inflation is to that goal. The Bureau of Labor Statistics publishes it at 8:30 a.m. Eastern Time on a date that changes every month (BLS release schedule). The next one is on When is the next US CPI report?
Read the gap, not the number
Before the release, economists publish a forecast, and the market prices it in. When the figure comes out, the only new information is the surprise: the actual figure minus the forecast.
Made-up numbers, not real releases:
- Forecast 2.7%, actual 3.0%: above the forecast. The currency tends to rise.
- Forecast 3.3%, actual 3.0%: below the forecast. The currency tends to fall.
- Forecast 3.0%, actual 3.0%: in line. Little reaction.
The same 3.0% appears in every row, with a different reaction each time. Know the forecast before the release. The forecast and the recent results against it are on US Inflation Rate (CPI).
Headline and core
- Headline CPI includes everything in the basket, food and energy too.
- Core CPI, “all items less food and energy”, leaves out the two prices that swing the most (BLS CPI questions and answers).
When the two disagree, the market often follows core, because it shows the underlying trend. A high headline from a jump in petrol prices is easier to look past than a high core reading. More in What Is Core Inflation?
The monthly change
The BLS reports both the 1-month and the 12-month change. The 12-month figure makes the news, but it carries a year of history and moves slowly. The 1-month change shows what prices did in the latest month alone.
A falling 12-month rate can hide a monthly figure that is picking up again. Traders who read only the yearly rate can overlook that turn.
Why the same figure can move price both ways
- Headline and core point in different directions.
- Positioning: when many traders already expect a high figure, a result only slightly above the forecast can still disappoint them.
- The trend: a figure above the forecast that is still the third fall in a row can read as inflation easing.
From inflation to the rate path
CPI does not move a currency on its own. It moves the expected path of interest rates, and the currency follows that path relative to other countries’ paths. A US CPI surprise matters most when it changes the gap between the Fed’s expected path and the others’. How the Fed shows its own path is in The Fed Dot Plot Explained.
Jobs are the other half of the Fed’s mandate. Reading the jobs report the same way is in NFP Trading Guide: How Non-Farm Payrolls Move the Dollar.