Crab, Bearish

Core idea

The bearish crab is a five-turn harmonic pattern (X-A-B-C-D) where each turn is qualified by a Fibonacci ratio of the prior leg. Visually it looks like a wide W with tall sides — or a "double bottom with point D way off in the boonies." The defining feature is that point D extends to 1.618 of XA — far higher than the prior peak — and price is supposed to reverse downward there.

The crab is the #1 performer in bull markets and #2 in bear markets among Fibonacci patterns by Bulkowski's measure (reversal-at-D rate). 87%+ of crabs see price turn lower at D. The trouble is what happens after the turn: the average drop is only 14% in bull markets, and 20% of crabs fail to drop more than 5% before reversing back up.

Why the layout differs from non-harmonic topics

Harmonic patterns aren't graded by post-breakout move; they're graded by whether price reverses at the predicted turn. So the statistics focus on (1) how often price reaches D, (2) how often it reverses at D, and (3) how far it travels after the reversal — not on breakout direction or measure-rule targets.

Why it matters

The crab is the cleanest example of a recurring trap: a high-quality reversal signal that produces a small reward. Knowing price will turn down at D is genuinely valuable — but if you can only extract 3-5% of move before the reversal busts, transaction costs, slippage, and short-borrow fees eat the trade. The crab is best used as:

1. A proactive exit signal for existing long positions ("turn likely at D — take profits"), not a primary short entry.
2. A filter combined with other bearish signals — overhead resistance, fundamental deterioration, sector weakness — that raise the expected move beyond 14%.

It also calls attention to a structural setup: a bullish pattern (double bottom, cup-with-handle) appearing inside a long topping pattern is often a bull trap. Many crabs sit exactly there — and many of the failures Bulkowski highlights resolve the bullish pattern's way, not the crab's.

Key takeaways

Mental model

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Practical application

Identifying a bearish crab

Trading the reversal at D

Example

A mid-cap industrial trades at $50 in July, falls to $42 (X), rallies to $46 (A), falls to $43.50 (B — a 0.5 retrace of XA, valid), rallies to $45 (C — within Fibonacci range of BA), then climbs in a tight uptrend to $51 (D). Check DC/BC: $51-$43.50 over $45-$43.50 ≈ 5 — too high. Pattern doesn't qualify.

Now imagine the same setup but D lands at $48.20. DC/BC = ($48.20-$43.50)/($45-$43.50) = 3.13 — within the 2.618-3.618 range. DA/XA = ($48.20-$42)/($46-$42) = 1.55 — outside the 3% window of 1.618. Still no crab.

Tweak A to $45.85, X to $42, D to $48.30. Now DA/XA = ($48.30-$42)/($45.85-$42) = 1.64, within 3% of 1.618. Valid bearish crab.

You wait two days after $48.30 prints. Price closes at $47.20 (confirmation of turn). You short 200 shares at $47, stop at $48.80. First target: B at $43.50 (covers half position). Two weeks later price hits $43.40 — you cover half for $700. Price chops between $43 and $45 for three more weeks, then breaks above $46. You cover the rest at $45.50 — net profit $1500 minus borrow fees. The crab worked, but the reward was modest. That's the pattern in a nutshell.

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