# Technical Analysis from A to Z

by Steven B. Achelis

ENVELOPES (TRADING BANDS)

Overview

An envelope is comprised of two moving averages. One moving average is shifted upward and the second moving average is shifted downward.

Interpretation

Envelopes define the upper and lower boundaries of a security's normal trading range. A sell signal is generated when the security reaches the upper band whereas a buy signal is generated at the lower band. The optimum percentage shift depends on the volatility of the security--the more volatile, the larger the percentage.

The logic behind envelopes is that overzealous buyers and sellers push the price to the extremes (i.e., the upper and lower bands), at which point the prices often stabilize by moving to more realistic levels. This is similar to the interpretation of Bollinger Bands'.

Example

The following chart displays American Brands with a 6% envelope of a 25-day exponential moving average.

You can see how American Brands' price tended to bounce off the bands rather than penetrate them.

Calculation

Envelopes are calculated by shifted moving averages. In the above example, one 25-day exponential moving average was shifted up 6% and another 25-day moving average was shifted down 6%.

*Technical Analysis from A to Z*is reproduced here with permission from the author and publisher.

### Contents

- Preface
- Acknowledgments
- Terminology
- To Learn More
- Bibliography
- About the Author
- Technical Analysis
- Price Fields
- Charts
- Support & Resistance
- Trends
- Moving Averages
- Indicators
- Market Indicators
- Line Studies
- Periodicity
- The Time Element
- Conclusion
- Absolute Breadth Index
- Accumulation/Distribution
- Accumulation Swing Index
- Advance/Decline Line
- Advance/Decline Ratio
- Advancing-Declining Issues
- Advancing, Declining, Unchanged Volume
- Andrews' Pitchfork
- Arms Index
- Average True Range
- Bollinger Bands
- Breadth Thrust
- Bull/Bear Ratio
- Candlesticks - Japanese
- CANSLIM
- Chaikin Oscillator
- Commodity Channel Index
- Commodity Selection Index
- Correlation Analysis
- Cumulative Volume Index
- Cycles
- Demand Index
- Detrended Price Oscillator
- Directional Movement
- Dow Theory
- Ease of Movement
- Efficient Market Theory
- Elliott Wave Theory
- Envelopes (Trading Bands)
- Equivolume/Candlevolume
- Fibonacci Studies
- Four Percent Model
- Fourier Transform
- Fundamental Analysis
- Gann Angles
- Herrick Payoff Index
- Interest Rates
- Kagi
- Large Block Ratio
- Linear Regression Lines
- MACD
- Mass Index
- McClellan Oscillator
- McClellan Summation Index
- Median Price
- Member Short Ratio
- Momentum
- Money Flow Index
- Moving Averages
- Negative Volume Index
- New Highs-Lows Cumulative
- New Highs-New Lows
- New Highs/Lows Ratio
- Odd Lot Balance Index
- Odd Lot Purchases/Sales
- Odd Lot Short Ratio
- On Balance Volume
- Open Interest
- Open-10 TRIN
- Option Analysis
- Overbought/Oversold
- Parabolic SAR
- Patterns
- Percent Retracement
- Performance
- Point & Figure
- Positive Volume Index
- Price and Volume Trend
- Price Oscillator
- Price Rate-of-Change
- Public Short Ratio
- Puts/Calls Ratio
- Quadrant Lines
- Relative Strength, Comparative
- Relative Strength Index
- Renko
- Speed Resistance Lines
- Spreads
- Standard Deviation
- STIX
- Stochastic Oscillator
- Swing Index
- Three Line Break
- Time Series Forcast
- Tirone Levels
- Total Short Ratio
- Trade Volume Index
- Trendlines
- TRIX
- Typical Price
- Ultimate Oscillator
- Upside/Downside Ratio
- Upside/Downside Volume
- Vertical Horizonal Filter
- Volatility, Chaikin's
- Volume
- Volume Oscillator
- Volume Rate-of-Change
- Weighted Close
- Williams' Accumulation/Distribution
- Williams' %R
- Zig Zag