Bollinger Bandwidth
Volatility & bands
The width of the Bollinger Bands, expressed as a percentage of the center line. This is the pure volatility gauge behind the bands.
Construction & calculation
- Bandwidth = (upper band - lower band) / center line.
- The scanner then sets that value against its own range over the last 100 bars, so each stock is judged on its own history.
Bandwidth = (Upper - Lower) / Center
position = (now - min(100 bars)) / (max(100 bars) - min(100 bars))
Interpretation
- A historically low bandwidth is the famous Squeeze: volatility has dried up. Bollinger called this the most reliable precursor of a big move.
- A historically high bandwidth is a Bulge: volatility is peaking. Such peaks usually coincide with panic or euphoria — and thus often with a turning point.
- Important: the Squeeze does not say in which direction the breakout comes, only that one is coming.
How the signal works in this scanner
Buy signal (green)The bandwidth is in the lowest 10% of its range over the last 100 bars: a Squeeze — a breakout is approaching.
Sell signal (red)The bandwidth is in the highest 10% of its range: a Bulge — volatility is peaking, which often coincides with exhaustion.
Watch-outs & pitfalls
- The bull and bear labels here are color codes, not a directional prediction. A Squeeze can just as easily break downward.
- Use this signal as an alarm: put the stock on your watchlist and let a directional indicator (Donchian, Keltner, MACD) determine which way you play it.
- Requires at least 60 trading days.