Methods and evidence
Market breadth vs the CNN Fear & Greed Index
A market-breadth measure and CNN's Fear & Greed Index answer different questions. Breadth asks how many stocks share a trend. CNN combines several market indicators into a sentiment reading. Their numbers can disagree without either calculation being broken.
What each number measures
| Measure | Inputs and meaning |
|---|---|
| PyInvesting breadth | The percentage of stocks in the tracked universe above their six-month exponential moving average (EMA). It describes participation in an uptrend. |
| CNN Fear & Greed | A composite of seven indicators, spanning price momentum, price strength, price breadth, options, volatility, safe-haven demand and junk-bond demand. It describes sentiment through multiple market signals. |
The live PyInvesting Fear & Greed page displays market breadth alongside the exposure and historical record of a related allocation rule. The breadth percentage, the portfolio's invested percentage and the portfolio's return are three different quantities. A 65% breadth reading does not mean a 65% stock allocation or a 65% chance that prices will rise.
Why the readings can diverge
Suppose 65 of 100 tracked stocks are above their six-month EMA. Breadth is 65%, even if the largest stocks fell today. Another measure may react to option prices, credit conditions or volatility that this calculation does not use. The indicators can also use different lookback windows and update times.
Always compare the input definition, universe, timestamp and horizon before comparing the labels. “Fear” on one scale is not a calibrated equivalent of “fear” on another. Neither is a direct survey of every investor's intentions.
Use breadth to ask a better research question
Instead of treating either number as an instruction to buy or sell, ask a specific question: does the trend have broad participation, or is it concentrated in a few constituents? Then define how you would evaluate that observation. Index weights matter: an equal-count breadth measure and a capitalization-weighted index can move differently.
Read what fewer stocks above a moving average means for a historical descriptive study. If you want to test an allocation idea, the worked allocation example separates the signal from the trading rule and its assumptions.
Sources and limits
CNN describes its methodology on the official Fear & Greed page. PyInvesting's methodology and latest observation are on its index page. The two products are separate; this comparison does not imply an affiliation with CNN.
Universe changes, missing data, lagging moving averages and subsequent data revisions can affect interpretation. These are research indicators, not reliable forecasts or personalized investment recommendations.