Inflation data has, since 2021, overtaken the jobs report as the release that moves markets most. The reason is simple: central banks say, in plain words, that their decisions depend on it. When the Consumer Price Index lands, the market is being told directly how much the Fed's next decision has changed.
The four numbers
The US CPI release contains four figures that traders watch, and it helps to know which one is which:
- Headline, month-on-month. How much prices rose since last month, all items. The freshest signal but the noisiest.
- Core, month-on-month. The same, excluding food and energy, which swing with weather and oil. This is the number the Fed watches most.
- Headline, year-on-year. Prices versus twelve months ago. Slow-moving; good for the trend, bad for surprises.
- Core, year-on-year. The "underlying" inflation rate. Rarely surprises by much.
In practice, the market reacts most to core month-on-month versus its forecast. A 0.2% print against a 0.3% forecast is "cool" and the dollar falls; 0.4% against 0.3% is "hot" and the dollar rises. The difference between those outcomes, on the day, can be a full percent on the dollar index and 2% on gold.
The chain of reasoning
It helps to say out loud what the market is doing in the seconds after the release:
- Inflation came in hotter than expected.
- Therefore the Fed is less likely to cut rates soon.
- Therefore US rates will stay higher relative to other countries.
- Therefore money flows into dollars. USD rises.
- Higher rates make non-yielding gold less attractive. Gold falls.
- Higher discount rates reduce the value of future company profits. Equities fall.
Reverse every line for a cool print. Once you have the chain, the reactions stop looking like separate events and start looking like one event seen from six angles.
The hour after
The first move is fast and usually correct in direction. What follows depends on the details. Two cases are common:
The clean print. Headline and core point the same way, the surprise is meaningful, and the move extends through the afternoon. These are the days that show up as long candles on daily charts.
The mixed print. Headline hot because of petrol, core cool. The first spike goes with the headline, then reverses within minutes as traders read the core figure. A copy that holds through this sees its equity jump one way and then the other; by the end of the hour it may be back where it started.
Gold on CPI day
Gold is the purest expression of the rate chain because it has no yield of its own. A hot print sends real yields up and gold down, often 1–2% in the hour. A cool print does the reverse. If you copy a gold master, CPI day is the day to expect your copy's equity to move most, in either direction, and the day the master's drawdown figure was most likely earned.
Other inflation prints worth knowing
CPI is the headline act, but the Fed's stated preference is a different measure: the PCE price index, published about two weeks later. It is built from the same underlying prices with different weights, so it rarely surprises once CPI is known — but a gap between the two can move the market on its own. The Producer Price Index (PPI), released a day or two after CPI, measures prices at the factory gate and is read as a hint of where consumer prices go next. Outside the United States, UK and eurozone CPI matter for the pound and euro in exactly the same way, and land at 07:00 and 10:00 GMT respectively.
A useful habit is to note the whole cluster: CPI, then PPI, then PCE. A month where all three point the same way is a month where the rate path has genuinely shifted, and the currency move will tend to persist. A month where they contradict each other is a month of whipsaws, and the best masters are the ones whose drawdown stays flat through it.
Three mistakes to avoid on CPI day
- Judging the print by the headline. Petrol prices can make a headline hot while core is cool; the market will follow core within minutes.
- Reading the first candle as the verdict. The first spike is algorithms; the direction after fifteen minutes is the market.
- Changing a copy because of one data point. One CPI print is one input to a rate path that spans two years. A master's record over twelve months already contains twelve of them.
What to do as a copier
Nothing dramatic. The practical habit is to look at the calendar on the morning of CPI, note the time (13:30 GMT, 12:30 in summer), note the core forecast, and then not touch anything at 13:31. The two mistakes new copiers make on data days are the same two, every time: stopping a master because of a spike that reverses within minutes, and switching the auto-stop off "so the trade has room" and then losing more than they ever intended. Set the auto-stop for a real disaster, leave it on, and let the master trade the hour.
Core month-on-month versus forecast is the number. Hot means fewer cuts, stronger dollar, weaker gold. Cool is the mirror. Everything else on CPI day is detail.
This article is education, not investment advice. Trading and copy trading in leveraged instruments carry a high risk of losing the funds you allocate. Read the Risk Disclosure.