Core Inflation Year-over-Year

Think of it this way

It is taking the patient's temperature without counting the time they spent in the sun. They may have less of a fever today because they moved into the shade, but that says nothing about whether the infection has cleared.

What is Core Inflation Year-over-Year?

Year-over-year inflation excluding food and energy. The idea is not that those prices do not count, but that they move for reasons no central bank controls: a drought, an OPEC decision, a war. Removing them leaves the underlying pressure, which is what responds to interest rates and therefore what tells the Fed whether its policy is working.

How to read Core Inflation Year-over-Year

Always look at them together, headline and this one. When headline is above, the problem is energy or food and usually corrects on its own. When core is above, the problem is underlying and much harder to solve: rents and wages do not fall because rates rise; it takes quarters. Lag: none; here inflation is the consequence, not the cause.

What Core Inflation Year-over-Year means for the market

It is the one that really shapes rate decisions. A headline inflation figure at 2% with core at 3.5% gives the Fed no room, and the market knows it: that is why stocks sometimes fall on an apparently good inflation print.

Where the money flows

Like headline inflation, it is the consequence and not the flow. The difference is which part of the path it captures: rents, service wages and insurance, which are prices that adjust slowly and reflect whether excess money has settled into the economy or whether it was just an energy scare.

What to watch in Core Inflation Year-over-Year

Overlay it on headline and see which one is higher. If headline is higher, the difference is energy and food, which can reverse on their own. The worrying case is the opposite, this one above headline, because it means the pressure is in rents and services, which take quarters to ease. And if it stays flat around 3% for several months, disinflation has stalled where it matters.

Inflation without food or energy. It is the one that really shows whether the problem is underlying.