A diagonal with diverging trendlines — each sub-wave is larger than the previous. Rare. The expanding ending diagonal appears at wave 5; the expanding leading diagonal appears at wave 1.
Description
An expanding diagonal is the opposite of the more common contracting diagonal — its boundary lines diverge rather than converge. Each successive sub-wave is larger than the preceding one. This pattern is rare and often difficult to identify in real time. The expanding ending diagonal still signals exhaustion and an impending reversal.
Key Points
- Trendlines diverge (opposite of contracting diagonal)
- Each sub-wave is larger than the previous
- Wave 3 must not be the shortest actionary wave (same rule as in a standard impulse)
- Expanding ending diagonal at wave 5 → still signals trend exhaustion and reversal
- Very rare — do not default to expanding diagonal unless contracting diagonal clearly does not fit
- Sub-wave structure: 3-3-3-3-3 (most commonly observed)
