CONCEPT · June 10, 2026

THE BASICS

What CPI is and why it moves the market

It's the number that moves stocks most every month, and almost nobody knows how it's actually built.

WHAT IT MEASURES

PRICES

what the consumer pays

HOW OFTEN

MONTHLY

once a month

WHY IT MATTERS

RATES

it sets the Fed's pace

THE IDEA

1 BASKET

a typical shopping cart, repeated each month

CPI tracks the price of a basket of goods and services a typical household buys. By comparing its cost month over month, it measures the inflation you actually pay.

THE FIGURE

EXAMPLE

≈ 80,000

prices collected each month (approximate figure)

Behind that 4% you see in the news are tens of thousands of real prices, from rent to a cup of coffee.

CPI is not a price, it's a giant average. Each month tens of thousands of prices are collected to build a single number.

AVERAGE: — Many values reduced to a single figure.
WEIGHTING: — The importance given to each item based on how much people spend on it.

SIMPLE RULE

THE KEY

It's not the level, it's the change

“CPI doesn't tell you how much life costs, it tells you how much more expensive it is than before.”

Ronfy Analysis · Editorial

The classic mistake is reading CPI as a price. What matters is its change versus the prior month or year.

CHANGE: — The shift in a value from an earlier point, in percent.
YoY: — Year over year. Compared with the same month a year ago.

ILLUSTRATION

HYPOTHETICAL EXAMPLE

What 4% inflation does to your money

YEAR 0YEAR 2YEAR 4YEAR 5YEAR 6

Inflation looks small each month, but it compounds. 4% a year erodes a quarter of your purchasing power in six years.

Illustrative curve, not real data. At an average 4% inflation, a basket that cost 100 costs about 125 six years later.

PURCHASING POWER: — How many goods you can buy with the same amount of money.
COMPOUND: — The effect of applying a rate on top of the prior period's result.

WHY IT MATTERS

THREE REASONS

Why one monthly print moves trillions

IT GUIDES THE FED
The central bank raises or cuts rates based on inflation. A hot CPI forces it to keep money expensive for longer.
IT RESETS YOUR MONEY
Pensions, wages, and some bonds adjust to CPI. If inflation rises, what you earn should rise with it.
IT PRICES STOCKS
More inflation means higher rates, and higher rates make growth stocks worth less today.

CPI is not just a statistic. It's the signal the central bank, the markets, and your own wallet all read.

RATES: — The price of money set by the central bank.
EXPENSIVE MONEY: — When borrowing costs a lot because rates are high.
INDEXING: — Adjusting an amount upward to offset inflation.

THE BASKET

HOW IT SPLITS

What's inside the CPI basket

HOUSINGRent and home costs, the biggest weight35%

TRANSPORTCars, gasoline, and transit17%

FOODGroceries and dining out14%

ENERGYElectricity, gas, and fuels7%

EVERYTHING ELSEHealth, leisure, clothing, education27%

Weights are approximate and illustrative. The point: housing dominates, which is why rents drive the inflation print.

Not everything weighs the same. Housing dominates, so a change in rents moves CPI more than the price of bread.

WEIGHT: — The importance given to each category in the CPI calculation.
CORE: — CPI excluding food and energy, the two most volatile categories.

TO APPLY IT

5 EXAMPLE ETFs

Five ways to get inflation exposure

TIP	~110	▲ ref.	Inflation-linked Treasuries. Their principal rises with CPI.
SCHP	~50	▲ ref.	Another basket of inflation-linked bonds, with low fees.
VTIP	~48	▲ ref.	Short-term inflation-linked bonds, less rate-sensitive.
DBC	~24	▲ ref.	A commodities basket. Tends to rise when inflation rises.
GLD	~400	▲ ref.	Gold. The classic hedge when inflation is feared to erode money.

These ETFs illustrate the concept: instruments whose value is tied, one way or another, to inflation. This is not a recommendation.

ETF: — A listed basket tracking an index or theme. Trades like a stock.
PRINCIPAL: — The amount invested in a bond, which in TIPS adjusts to CPI.

WRAP-UP

Is CPI clear now?

If you now get what it measures and why it matters, share it with someone who always mixes it up.

One concept a day, explained from scratch. No jargon, no fluff.

Daily briefing · Mon-Fri 16:00 ET

CPI: — Consumer Price Index. The most-watched measure of inflation.
INFLATION: — The broad rise in prices over time.

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