Hot Share: how much of the market sits in the top turbulence bands

The nearest common idea is market breadth, or informally, the share of stocks that are highly volatile right now. Breadth is usually read off advance/decline lines or the count of stocks above a moving average. Hot Share measures it structurally instead: the percent of the whole universe sitting in the top two turbulence bands, High or Extreme, on a given session-day.

It is a bottom-up number, not an index one. The VIX and index volatility describe the market as a single object. Hot Share describes the population underneath it: how many individual companies are moving in wide ranges. The two can diverge, and the gap is often the interesting part. A calm index can sit over a market where a large and rising share of names are individually turbulent.

Why measure it this way

An index-level volatility reading averages everything together and hides dispersion. Counting companies band by band keeps the dispersion visible. Hot Share answers a plain question, how much of the market is currently unsettled, and pairs naturally with warming, which asks whether that share is still growing.

How it is measured

Every company in the universe is assigned a turbulence band from its recent daily price history. Hot Share is the percent of the banded universe in High or Extreme. It is always a share of that day’s banded universe, so the denominator is published alongside every reading; when the tracked universe changes size, that shows in the record rather than being smoothed away.

A share, not a direction

A high Hot Share means a wide range of movement is spread across many names. It does not say which way those names go. Turbulence sizes the range; it does not point it. Hot Share is descriptive structure, not a signal to buy or sell.

Today’s reading, and the record

Hot Share is published every session-day in the Daily Breadth dataset, with the full band distribution and per-sector warming. The live figure at the top of this page is today’s, and the dataset is the permanent series.

Descriptive, not advice. See it at work in the daily Market Analysis.