What is a Descending Triangle? Definition, Formula, and Example
A descending triangle is a bearish continuation chart pattern formed by a horizontal support line and a series of lower highs, which resolves with a breakdown through support on expanding volume.
Plain-English Definition
A descending triangle is a bearish chart pattern built from two specific structures: a flat horizontal support line at the bottom and a downward-sloping trendline of lower highs at the top. Price oscillates inside the narrowing range until sellers exhaust buyers at support, producing a downside breakout. It is the mirror image of the ascending triangle and is classified as a continuation pattern in downtrends and a reversal pattern at the top of uptrends.
How It's Identified
A valid descending triangle requires four mechanical conditions:
1. Horizontal support — at least two distinct touches at roughly the same price (within 0.5%–1.0% tolerance).
2. Lower highs — at least two, ideally three, forming a clean descending trendline.
3. Volume contraction — total volume should fade as the apex approaches.
4. Breakdown confirmation — a close below support on volume ≥ 150% of the 20-day average.
Measured price target: subtract the vertical height of the pattern (the distance from horizontal support to the first lower high) from the breakdown point.
Target = Support − (First High − Support)
Worked Example
META carved a textbook descending triangle from late August through October 2022. Support sat at $135.50 with three precise touches on Aug 23, Sept 14, and Oct 13. The descending trendline connected lower highs at $180.10, $164.45, and $147.20. Pattern height = $180 − $135 = $45.
On Oct 27, post-earnings, META gapped through support and closed at $97.94 on 191M shares — 3.2× average volume. The measured target of $90 ($135 − $45) was hit within two sessions, and the stock continued to $88.09 by Nov 4 before the multi-month bottoming process began.
When Traders Use It
- Swing shorts enter on the confirmed breakdown candle with a stop above the most recent lower high.
- Aggressive traders short into rallies that fail at the descending trendline before the breakdown, sizing smaller because the pattern hasn't resolved.
- Long-only managers use the pattern as a risk-management trigger — lightening positions before support fails rather than waiting for the breakdown.
- Algo systems scan for the pattern via piecewise linear regression on highs combined with horizontal-level clustering algorithms.
The pattern is most reliable when the prior trend was already down (continuation context) and when it forms on a daily or weekly chart with at least 30 sessions of development time.
Limitations and Common Misconceptions
The biggest misconception is that descending triangles always break down. Thomas Bulkowski's pattern statistics show roughly a 64% downside resolution rate — meaningful, but far from certain. The remaining ~36% break upward, often violently, producing what looks like a bull trap in reverse.
Other limitations:
- Strong uptrends override the pattern. A descending triangle inside a screaming bull market (rising 50-day above 200-day, sector breadth positive) frequently fails.
- Time matters. Patterns developing over fewer than 20 sessions are unreliable noise.
- Volume divergence is required. A descending triangle on rising volume often signals accumulation rather than distribution.
- Apex risk. Once price reaches the convergence of both lines without resolving, the pattern loses predictive power.
Position-size for failed breakdowns. The pattern's edge is statistical, not deterministic.