Consumer Price Index (CPI): Measuring Inflation
The Consumer Price Index tracks changes in the price of a fixed basket of goods and is the most-watched inflation gauge for traders and central banks.
Consumer Price Index (CPI): Measuring Inflation
The Consumer Price Index (CPI) is the most widely followed measure of inflation. Released monthly by the Bureau of Labor Statistics, CPI tracks the average change in prices that urban consumers pay for a fixed basket of goods and services. When CPI prints, every market reacts.
How CPI is built
The BLS surveys prices across thousands of items in categories like housing, food, transportation, medical care, and apparel. Each category is weighted by how much of the typical household budget it consumes.
| Category | Approximate weight |
|---|---|
| Housing (shelter) | ~33% |
| Food | ~14% |
| Transportation | ~16% |
| Medical care | ~8% |
| Energy | ~7% |
Headline vs. core CPI
- Headline CPI — includes all items, including food and energy
- Core CPI — excludes food and energy, which are volatile
Central banks focus on core because it reveals the underlying inflation trend. Markets watch both — a hot headline can move price even when core is tame.
Why CPI moves markets
Inflation drives interest rate decisions. Higher CPI pressures the Fed to hike; softer CPI opens the door to cuts. Rate expectations then drive currencies, bonds, and equities.
| CPI surprise | USD reaction | Equity reaction |
|---|---|---|
| Hot CPI beat | Bullish | Bearish (rate-hike fear) |
| In line | Minimal | Minimal |
| Soft miss | Bearish | Bullish (rate-cut hope) |
How to read the report
Each release shows three numbers: MoM (month-over-month), YoY (year-over-year), and Core (excluding food and energy). YoY is the headline number most traders cite. A 3.5% YoY CPI means prices are 3.5% higher than a year ago.
Trading the CPI release
CPI releases at 8:30 AM New York on a monthly schedule. The pattern mirrors NFP — an explosive first two minutes followed by a more tradable move. Note the forecast and prior values, reduce exposure 10 minutes before, wait 5–15 minutes for the spike to settle, and trade the direction confirmed by the surprise vs. forecast. Use a wider stop than normal — CPI can reverse quickly.
Common pitfalls
- Trading the headline only — core matters more for the trend
- Ignoring shelter — housing is the largest weight and a slow-moving force
- Forgetting base effects — a high reading a year ago makes today's YoY look low even if prices rose
Watch CPI alongside PCE (the Fed's preferred measure) and PPI (producer prices, an upstream signal). CPI is the inflation benchmark — pair it with rate expectations and you understand the single biggest force in macro trading.