Compression and Expansion

Volatility moves in cycles. Periods of small, tightening ranges, called compression, are often followed by periods of large, fast moves, called expansion. Then the cycle repeats. Traders sometimes summarise it as "quiet markets get loud and loud markets get quiet." Recognising compression helps you prepare for a breakout before it happens, rather than chasing it afterwards.

What compression looks like#

• Candle ranges shrink day after day.
• Highs get lower and lows get higher, forming a triangle or wedge. See Symmetrical Triangle.
• Bollinger Bands narrow, sometimes called a squeeze. See Bollinger Bands.
• Average true range falls to a low reading relative to recent history. See ATR (Average True Range).
• Volume often declines as participants wait.

Why compression leads to expansion#

During compression, buyers and sellers are balanced and orders build up just above and below the narrowing range: breakout entries, stop losses from both sides and waiting buyers and sellers. When price finally breaks out, those orders trigger together, producing a burst of activity. Volatility itself also tends to revert to its average, so extremely low volatility rarely lasts.

Measuring compression#

Trading expansion#

1. Mark the compression range: the high and low of the tight area.
2. Plan both directions, unless the trend gives a bias. Compression in an uptrend more often resolves upward, but not always.
3. Enter on the break: a stop order just outside the range, or wait for a candle close beyond it.
4. Stop inside or on the other side of the range. Tight compression allows tight stops.
5. Target using volatility: expansions often travel several times the compressed range.

See Breakouts for entry details.

Traps to watch for#

• False breaks: compression often ends with a fake move in one direction before the real move in the other. See Failed Breakouts and False Breaks.
• News timing: compression ahead of a scheduled event often resolves at the event, with gaps that skip stop orders.
• Low volatility can persist: some markets stay quiet longer than expected, producing many small losses on early breakout attempts.

Expansion into exhaustion#

The cycle continues after the breakout. Expansion phases end with very large candles, high volume and sometimes climactic reversals, after which a new compression begins. Recognising late, overextended expansion helps you avoid buying at the end of a move. See Impulse and Correction.

Common mistakes#

• Waiting for expansion to start before noticing compression, then chasing.
• Expecting a direction without evidence; plan for both.
• Using wide stops after a tight compression; the setup's value is the tight risk.

Frequently asked questions#

What is compression in trading?#

A period of shrinking price ranges and falling volatility, often forming a tightening pattern before a breakout.

What is a Bollinger Band squeeze?#

When Bollinger Bands narrow sharply, signalling low volatility that often precedes a large move.

Which direction will price break after compression?#

There is no guaranteed direction. The prior trend and higher timeframe structure offer clues, but traders often prepare for both.

Next, learn the most widely used concept in charting: Support and Resistance.