Bollinger Bands
![S&P 500 with 20-day, two-standard-deviation Bollinger Bands, %b and bandwidth.](/Images/godic/202501/01/BollingerBandsSPX.svg4142.png")
Bollinger Bands is a technical analysis tool invented by John Bollinger in the 1980s as well as a term trademarked by him in 2011. Having evolved from the concept of trading bands, Bollinger Bands and the related indicators %b and bandwidth can be used to measure the "highness" or "lowness" of the price relative to previous trades. Bollinger Bands are a volatility indicator similar to the Keltner channel.