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Harmonic patterns — Gartley, butterfly, bat
The Fibonacci-based reversal patterns institutions watch. How to find them and price them.
Harmonic patterns (Gartley, butterfly, bat, crab) are five-point structures (X-A-B-C-D) where each leg must retrace a specific Fibonacci ratio of the prior leg. The Gartley looks for a D-leg that completes near the 0.786 retracement of XA; the butterfly extends beyond X; the bat compresses tighter with a 0.886 XA retracement.
These aren't visual patterns you eyeball — they're measured. A pattern that's "close enough" by eye and off by 10% on the ratios isn't a harmonic pattern, it's a coincidence. Use a Fib tool and check every leg before trusting the D-point as a reversal zone.