How to Trade CPI Inflation in Forex

How to trade CPI inflation in forex starts with one habit: know the forecast before the number lands, because the currency moves on the gap between the two. The figure on its own tells you very little.

What the index measures is in What Is CPI (Consumer Price Index)? This page is about the minutes around the release and what to read in which order. None of it says which way a currency will move next.

Why inflation moves a currency at all

A central bank tends to raise rates when inflation runs above its target and to cut them when it runs below. Higher expected rates tend to draw money into a currency. So a CPI report matters to the extent that it changes what the market thinks the central bank will do.

Each bank writes its target on its own measure:

• The European Central Bank aims for 2% over the medium term on the HICP, and says that commitment is symmetric: it counts inflation below 2% as just as undesirable as inflation above it (ECB).
• The Bank of England has a 2% CPI target set by the UK government. If inflation is more than one percentage point away from it, the Bank has to tell the government why in writing (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 its job; maximum employment is the other half (the dual mandate).

US CPI still moves the dollar more on the day. It lands about two weeks before PCE, which is built largely from CPI prices, so by the time PCE comes out there is less left to surprise. The Bureau of Labor Statistics publishes it at 8:30 a.m. New York 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 trades as if it were already true. When the figure comes out, the only new information is the surprise: actual minus 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. Usually little reaction.

The same 3.0% sits in every row, with a different reaction each time. Write the forecast down before 8:30. It and every recent result against it are on US Inflation Rate (CPI).

Four numbers, and the order to read them

The release gives headline and core, each as a 1-month and a 12-month change (BLS CPI questions and answers). Headline is the whole basket. Core, “all items less food and energy”, leaves out the two prices that swing the most.

The yearly headline makes the news, but core on the month is the figure many traders read first. Say headline comes in below the forecast because petrol fell, and core comes in at 0.4% against 0.3%. The headline looks soft. The part the central bank cares about for its next decision got firmer. Markets tend to follow core in that case, because a jump in petrol is easier to look past than a broad rise in services. More in What Is Core Inflation?

Why the yearly rate can fool you

The 12-month rate adds the newest month and drops the one from a year ago. Which month drops out matters as much as the new one.

June 2023 shows it. Headline CPI fell from 4.0% in May to 3.0% in June, a big step (BLS, May 2023; BLS, June 2023). Prices in June 2023 rose only 0.2% on the month, though. Most of the fall came from the month that left the window: June 2022, when prices had jumped 1.3% in a single month (BLS, June 2022).

June 2023 was no one-off. Of the 221 months from March 2008 to September 2026, the headline 12-month rate fell in 97, and in 49 of those prices still rose on the month as first published. For core it was 66 of 83. The largest such steps in the headline were a full point, both in 2023: June, and before it March, when the yearly rate went from 6.0% to 5.0% on a month in which prices rose 0.1%.

That count reads the 12-month rate from the unadjusted index and the monthly change from the seasonally adjusted one, as the BLS does, both rounded to one decimal and both as the BLS first published them (the St. Louis Fed’s archive of past versions, with core read the same way). The seasonal factors behind the monthly change are revised every year; on today’s figures the count is 56 of 97, and 69 of 82 for core.

So before a release, look at what is about to drop out. You can often tell which way the yearly rate will move before you see a single new price. The monthly change is the cleaner read of what prices are doing now.

Why the same figure can move the 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.

That is why the first move after 8:30 is the part to trust least: it often trades the headline alone, and the next few minutes trade the rest.

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 against other countries’ paths. A US CPI surprise matters most when it changes the gap between where the Fed is expected to go and where the others are. How the Fed shows its own path is in The Fed Dot Plot Explained.

Subtract inflation from a policy rate and you get the real rate, a rough measure of how tight a central bank really is. Each economy’s is on Real interest rates by currency.

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.