What are Bollinger Bands?

Bollinger Bands

If you’ve ever looked at a stock chart and seen three curved lines wrapping around the price, chances are you were looking at Bollinger Bands. Created by John Bollinger in the 1980s, Bollinger Bands are one of the most popular technical indicators in trading today. They help traders understand volatility, spot overbought and oversold levels, and even predict potential breakouts.


What are Bollinger Bands?

Bollinger Bands are made up of three lines:

  • Middle Band → 20-day Simple Moving Average (SMA).
  • Upper Band → 2 standard deviations above the SMA.
  • Lower Band → 2 standard deviations below the SMA.

These bands expand when volatility rises and contract when volatility falls.


How to Read Bollinger Bands

  • Price Near Upper Band → Possible overbought zone.
  • Price Near Lower Band → Possible oversold zone.
  • Bands Contracting → Market may be preparing for a breakout.
  • Bands Expanding → Strong trend already in place.


How to Read Bollinger Bands with Stock Examples

  • When TCS stock trades near the upper band, it often signals an overbought zone where price may cool down.
  • When Infosys stock touches the lower band, it can indicate oversold conditions and a possible bounce.
  • During quiet phases, like HDFC Bank before quarterly results, the bands contract. After the results, if price breaks out, the bands expand rapidly.


Bollinger Band Trading Strategies with Examples

1. Bollinger Bounce

Stock prices often “bounce” between the upper and lower bands.

  • Example: In HDFC Bank, when the price touched the lower band in May 2023, it rebounded back towards the middle band before resuming the uptrend.

2. Bollinger Squeeze

When bands contract tightly, it signals low volatility and a possible breakout.

  • Example: In Reliance Industries (RIL), a tight squeeze formed in July 2022. Soon after, the price broke above the upper band, starting a strong rally.

3. Riding the Bands (Trend Trading)

In strong trends, stocks often “ride” the bands.

  • Example: Adani Enterprises in early 2021 consistently hugged the upper Bollinger Band during its sharp uptrend.
  • Example: Yes Bank in 2018 kept trading near the lower band for months, confirming bearish momentum.


Advantages of Bollinger Bands

✔ Easy to understand and visualize

✔ Helps identify volatility phases and breakouts

✔ Works across stocks, indices, forex, and crypto


Limitations of Bollinger Bands

❌ Alone, they don’t tell you trend direction (need RSI or MACD)

❌ Can give false overbought/oversold signals in strong trends


Combining with Other Indicators

  • In Infosys, if the stock touches the lower band while RSI is below 30, traders see it as a stronger buy signal.
  • In Tata Motors, a Bollinger Band squeeze + MACD crossover confirmed a big breakout in 2021.