Bollinger Bands are one of the most widely used volatility indicators in technical analysis, and for good reason. They give you a visual representation of where price is trading relative to recent market noise, helping you spot potential breakouts, identify squeeze setups, and catch mean reversion trades. Whether you're trading FTSE 100 blue chips or smaller FTSE 250 stocks, understanding how to read and use Bollinger Bands can sharpen your trading edge. In this guide, we'll walk through exactly how Bollinger Bands work, the key patterns to watch for, and how to avoid the common pitfalls that catch most traders out.
What Are Bollinger Bands?
Bollinger Bands are a three-line indicator consisting of a middle line (the simple moving average) and two outer bands positioned above and below. The standard settings are 20 periods and 2 standard deviations, which means the upper and lower bands sit exactly 2 standard deviations away from a 20-period simple moving average (SMA).
Here's what that means in practical terms: if price is normally distributed (which it roughly is), approximately 95% of all price action should touch the bands during normal trading. That 20-period SMA in the middle acts as a dynamic equilibrium—when price is above it, the market is leaning bullish; when it's below, the market is leaning bearish. The bands themselves represent zones of extreme price action.
The beauty of Bollinger Bands is that they're adaptive. They expand when volatility increases and contract when volatility decreases. Unlike fixed support and resistance levels, Bollinger Bands adjust to what the market is actually doing right now, not what it did last month or last year. This makes them especially useful in today's fast-moving markets.
How to Read the Bands: Expansion, Contraction, and Squeeze
The relationship between the bands tells you a huge amount about the current market environment. There are three key states to understand.
Expansion happens when volatility is rising. The bands move further apart, and price is making bigger moves relative to the moving average. You'll typically see expansion following a breakout, an earnings announcement, or a significant news event. On a chart of a FTSE 100 stock like Shell or HSBC, you might see the bands widen dramatically following a major earnings surprise. This expansion tells you the market is in an energetic, volatile state—not necessarily bullish or bearish, but certainly active.
Contraction is the opposite: the bands squeeze closer together as volatility dries up. Price is making smaller moves. This often happens in the lead-up to big news events or during quiet market periods. You'll see less price movement, fewer big wicks, and the bands getting narrower. Think of contraction as the market taking a breath before the next big move.
The Bollinger Squeeze is a specific form of contraction that deserves special attention. This is where the bands are unusually narrow—often the narrowest they've been in 6-12 months. The squeeze is one of the most powerful setups in technical analysis because it precedes explosive moves. When you see a tight squeeze on your chart, you're essentially looking at coiled energy. The market is quiet, but it won't stay quiet for long. A large move is coming—you just don't know which direction yet.
The Bollinger Squeeze: Low Volatility Precedes Big Moves
Many traders set alerts for Bollinger Squeezes because they're genuinely predictive. When the bands compress to their lowest point in months, price is about to make a significant move. This isn't magic—it's mathematics. When volatility is abnormally low, it must eventually normalize. And when it normalizes, price moves.
Here's how to trade it: identify the squeeze on your chart, note the breakout levels (usually just above the upper band and just below the lower band), and then set alerts. When price breaks above the upper band or below the lower band with volume, that's your signal that the energy has been released. The direction doesn't matter for identifying the setup—only that a big move is imminent.
A classic example on a FTSE 250 stock: imagine Rolls-Royce has been grinding sideways between 150p and 160p for three weeks with the Bollinger Bands squeezed tight as a vice. Then a contract announcement breaks and price gaps up through the upper band on heavy volume. That's the squeeze playing out. Traders who were watching for the squeeze didn't care whether it would be up or down—they just knew it was coming.
The key to trading squeezes successfully is patience. Don't try to guess the direction during the quiet period. Just wait. When the bands explode outward and price breaks decisively beyond one of them, that's when you act. Many traders make the mistake of entering trades during the squeeze itself when volatility is low. That's backwards. You want to enter when the squeeze is broken and the move has begun.
Walking the Bands: Strong Trend Signals
When price is in a strong, sustained trend, it will often "walk" along the outer bands. In an uptrend, price repeatedly touches or trades near the upper band; in a downtrend, it stays near the lower band. This is one of the most reliable visual confirmations that a trend is genuine and strong.
Think about what this means: if price is consistently running along the upper band, it means the market is persistently buying at higher and higher levels. That's the definition of a strong uptrend. Similarly, if price is hugging the lower band, every little bounce is being sold back down—a sign of strong bearish pressure.
On a chart of a FTSE 100 stock like Diageo or Unilever, during a sustained uptrend, you'll see price painting a series of higher highs and higher lows while staying near or touching the upper band. The middle SMA acts as support on pullbacks. This is textbook trend behaviour. The bands aren't fighting the price action; they're confirming it.
A practical trading rule: if price is walking the upper band, the trend is your friend. You can use pullbacks to the middle moving average (the 20-period SMA) as entry points for new long positions. Wait for a pullback from the upper band down to the SMA, and when price bounces away from the SMA, that's a solid continuation trade in a strong uptrend. Set your stop loss just below the SMA, and your profit target somewhere near the upper band again.
Bollinger Band Bounce: Mean Reversion Strategy
Not every trade is about following the trend. Sometimes the best opportunity is a mean reversion play, and Bollinger Bands are excellent for this.
Mean reversion is the idea that price extremes don't persist—when price gets pushed to an extreme (like touching the upper or lower band), it tends to snap back toward the middle. This is especially true in range-bound, non-trending markets.
Here's the setup: price touches or slightly breaches the upper band, and you expect it to bounce back down toward the middle SMA. Conversely, when price touches the lower band, you're looking for a bounce back up. The key qualifier is that this works best when the market is range-bound and not in a strong trend. If price is walking the bands (which we covered above), you don't want to fade that—you want to trade with it.
The signal to enter a mean reversion trade is when price touches the band with a large candle or wick. Imagine a FTSE 100 stock like Rio Tinto touching the lower band on a big down candle. That's often a capitulation move—sellers exhausted. The very next candle could reverse and walk back up toward the SMA. Your entry is at the signal candle's close or the next candle's open, stop loss just below the lower band, and target is the middle SMA.
This works because the bands are statistical constructs. Price at the 2-standard-deviation level is, by definition, an extreme. And extremes correct. Not always immediately, but with enough frequency that this becomes a viable trading edge.
Double Bottom (W Pattern) with Bollinger Bands
One of the most reliable patterns you can trade with Bollinger Bands is the double bottom, often called the W pattern. This is a reversal pattern that forms near the lower band and signals a bullish turn.
Here's what you're looking for: price drops down and touches the lower band (first bottom). It bounces back toward the middle, but then drops again and touches the lower band a second time at roughly the same level or slightly higher (second bottom). The key is that both bottoms touch or come very close to the lower band, confirming they're at similar levels of market stress.
After the second bottom, price reverses firmly upward. This is a high-probability reversal pattern. Why? Because it shows that buyers had to fight twice to defend that lower level. The first drop and bounce might be a bear trap. But the second bottom at the same level, followed by a strong recovery, tells you there's genuine buying interest.
On a FTSE 250 stock like Taylor Wimpey or Barratt Developments (particularly sensitive to economic sentiment), you'll often see W patterns form near the lower band following economic concerns. Each dip to the lower band is a flush of weak hands. By the second time, the buying pressure overwhelms the selling, and you get a sustained rally.
To trade this: draw a line connecting the two bottom points (where they touch the lower band). Once price closes above that line with volume, you have a completed W pattern. Enter a long position, set your stop just below the second bottom, and target a move to the upper band or beyond.
Combining Bollinger Bands with RSI or MACD
Bollinger Bands alone are powerful, but combining them with momentum indicators like the Relative Strength Index (RSI) or Moving Average Convergence Divergence (MACD) adds confirmation and filters out false signals.
Bollinger Bands + RSI: When price touches the upper band, check the RSI. If RSI is above 70 (overbought), price might be extended and due for a pullback. But if RSI is still below 70 and price keeps pushing higher toward the band, that's a sign of strong momentum—the move isn't tired yet. Conversely, when price touches the lower band with RSI below 30 (oversold), you have a powerful mean reversion setup. Price is at an extreme level and momentum is also depleted. A bounce is highly likely. If price touches the lower band but RSI is still above 30, the downtrend still has energy, and that's not a good mean reversion spot.
Bollinger Bands + MACD: Use MACD to confirm breakouts from Bollinger Squeezes. When the bands are tight and squeezed, watch the MACD lines. If they're also tight and about to cross, that's a two-stage confirmation that a breakout is coming. When the squeeze breaks, check if the MACD is also turning (lines crossing). If both the Bollinger Bands and MACD are confirming the breakout direction, your confidence level goes way up. This combination filters out many false breakouts that happen during choppy, indecisive price action.
Settings: Standard 20,2 vs Other Configurations
The standard Bollinger Band settings are 20 periods and 2 standard deviations. These work well for daily charts on most liquid stocks, including FTSE constituents. But settings aren't one-size-fits-all.
Shorter timeframes (4-hour, 1-hour, 15-minute): You might use a 10-period SMA with 1.5 standard deviations. This makes the bands more responsive and generates more signals. Useful for day traders catching intraday moves.
Longer timeframes (weekly, monthly): A 50-period SMA with 2 standard deviations works well for swing traders and position traders. The longer period smooths out daily noise and focuses on the bigger picture.
Tighter bands (using 1.5 standard deviations instead of 2): This makes the bands narrower, giving you more frequent signals and tighter stops. Some traders prefer this for more active trading.
Wider bands (using 3 standard deviations): This creates bands that price rarely touches, useful for identifying truly extreme moves. Some use this as a secondary band to show rare, crisis-level volatility.
The key is to test and stick with what works for your timeframe and trading style. Don't constantly fiddle with settings. Pick one set, learn it thoroughly on 50+ trades, and only change if you have a good reason.
Common Mistakes with Bollinger Bands
Understanding what NOT to do is as important as knowing what to do. Here are the mistakes that cost traders money:
Mistake 1: Trading every band touch. Not every touch of the upper band is a sell signal, and not every touch of the lower band is a buy signal. Context matters. If price is walking the bands in a strong trend, band touches are continuation signals, not reversals. Only trade mean reversion when the market is range-bound.
Mistake 2: Ignoring the band direction. Watch whether the bands are expanding or contracting. If they're expanding, volatility is rising, and you should expect bigger moves. If they're contracting, be cautious with your position sizing because a squeeze is coming. Many traders get stopped out because they expected normal volatility in a low-volatility squeeze environment.
Mistake 3: Using Bollinger Bands alone in choppy markets. When the market is choppy and indecisive, Bollinger Bands can whipsaw you. Price will touch both the upper and lower bands multiple times. Without confirmation from another indicator (volume, RSI, price structure), you'll get chopped up. Add filters.
Mistake 4: Setting stops above or below the band. This is backwards. If you're trading a mean reversion setup at the upper band, your stop should be just outside the band—not miles away. A stop above the upper band makes no sense because that's where you're expecting price NOT to go. Keep your stops tight and logical.
Mistake 5: Not considering the market environment. Bollinger Bands work differently in trending markets versus ranging markets. In a strong trend, price will walk the bands for days or weeks. In a range, price will bounce between them. Know which environment you're in before you trade.
Mistake 6: Overweighting the indicator. Bollinger Bands are a tool, not a holy grail. Combine them with price action, volume, and support/resistance levels. Price is always the primary information source. The Bollinger Bands are just helping you interpret it.
Putting It All Together
Bollinger Bands work because they're grounded in market structure and probability. They show you where price is relative to recent equilibrium, they adapt to changing volatility, and they highlight extremes that often reverse. From identifying tight squeezes that precede big moves, to spotting double bottoms near the lower band, to confirming trend strength when price walks the bands—these applications cover most of the trading scenarios you'll encounter.
The best way to learn is to pull up a chart of a FTSE 100 or FTSE 250 stock you follow, set Bollinger Bands to the standard 20,2 settings, and observe. Watch how the bands behave in different market conditions. Notice when squeezes form, when price walks the bands, and when mean reversion plays work. After 50-100 observations, the logic becomes intuitive. Then you can start trading with confidence.
