Bollinger Bands
Technical analysisA moving average with bands placed a set number of standard deviations above and below.
They define what is statistically normal for this stock — not what is expensive.
Every term is defined twice: once the way a filing would put it, and once the way somebody would explain it to you across a table. The second one is usually the one that sticks.
Showing 3 terms
A moving average with bands placed a set number of standard deviations above and below.
They define what is statistically normal for this stock — not what is expensive.
A contraction of Bollinger Bands to an unusually narrow width, indicating collapsed volatility.
Predicts the size of the coming move, never its direction.
A statistical measure of how widely a series is dispersed around its own average; Bollinger Bands sit two of them either side of a 20-day mean.
It is recomputed every session, which is why the bands widen when a stock turns volatile and contract when it goes quiet. Touching a band means statistically unusual, never expensive.