Question of the Week: What is the AB=CD Pattern?
- Kelsy
- Feb 1
- 5 min read
Welcome to PhantomSpot's Blog.
This post is adapted from the Question of the Week, a recurring discussion topic inside the PhantomSpot Discord. Periodically, members explore a technical concept, market structure idea, or analytical framework as part of an ongoing educational conversation.
The goal of these posts is not to provide trade signals or predictions, but to share how certain tools and patterns are commonly identified, discussed, and evaluated within the community. This content is provided for educational purposes only.
This post starts with a brief overview of the AB=CD pattern, then walks through a real INTC example to show how I evaluate structure in practice. It takes about 5 minutes to read.
What is the AB=CD Pattern?
The AB=CD pattern is a classic harmonic structure used in technical analysis to identify potential areas of price symmetry. It focuses on measured moves within the market, where an initial price leg (AB) is followed by a corrective move (BC), and then a subsequent leg (CD) that often mirrors the length and duration of AB.
Rather than predicting outcomes, the pattern is used to help frame potential areas where price may react based on proportional movement.
Structure Overview
The AB=CD pattern consists of four price points and three legs:
AB: Initial impulse move
BC: A corrective retracement of the AB leg
CD: A secondary impulse move that often aligns proportionally with AB in both price and time
Bullish vs. Bearish Variations
The pattern can appear in both bullish and bearish forms:
A bullish AB=CD typically appears as a downward zig-zag, where the CD leg completes near a potential support zone.
A bearish AB=CD often appears as an upward zig-zag, where the CD leg completes near a potential resistance area.
Common Ratio Relationships
While exact measurements can vary, the following relationships are commonly monitored:
BC retracement of AB: often around 0.618 or 0.786
CD extension of BC: commonly 1.272 or 1.618
AB ≈ CD: in both price distance and time duration
Not Every Zig-Zag Is an AB=CD Pattern
One of the most common mistakes newer traders make is assuming that any zig-zag price movement qualifies as an AB=CD pattern. While the structure can appear visually simple, not all swings meet the proportional and symmetry requirements that make the pattern meaningful.
For an AB=CD pattern to be considered valid in my own analysis, I look for several key characteristics working together—not just the shape.
What I Look For in a Valid AB=CD
Proportion between AB and CD
The AB and CD legs should be reasonably similar in magnitude. They do not need to be perfectly equal, but clear imbalance may reduce the usefulness of the pattern.
A reasonable BC retracement
The BC leg should retrace a proportion of AB without becoming excessively deep. In most cases, I look for BC to fall within a typical Fibonacci retracement range (often between 38.2% and 78.6%, with 61.8% commonly observed).
Respect for Fibonacci symmetry
The pattern should align with common Fibonacci relationships, particularly when projecting the CD leg from BC. This helps frame areas where price may react, rather than assuming continuation or reversal.
When these elements are missing, a zig-zag may simply represent noise or a standard corrective move rather than a structured AB=CD setup.
Applying the Framework: INTC Example
With that framework in mind, the following Intel (INTC) example walks through how I apply the AB=CD concept in practice using TradingView's built-in pattern tools alongside Fibonacci retracements.
This is a larger-scale example, chosen intentionally over short-term scalping setups. On this chart, a defined swing high formed on October 28th, 2025, followed by a retracement into November 10th, and then a swing low on November 21st.
The ABCD Pattern tool was used on TradingView to plot it.
If I draw a Fibonacci retracement from A to B, the C point falls between the 50% and 61.8% levels.
Evaluating the CD Leg (Flexibility Matters)
The next chart shows the check to see if the CD leg is a 127.2% to 161.8% extension of the BC retracement.
In this case, price did not cleanly complete within that textbook 127.2% to 161.8% extension range. However, when I zoomed out and compared the AB and CD legs directly, the symmetry in price distance was notable, even if the timeline differed. Check that out in the next charts. For me, that proportional relationship still carries weight, especially when combined with prior structure and momentum.
AB=CD Measurements
AB lost $6.56 in 87 bars.
CD lost $6.70 in 140 bars.
This displayed a similar price decline, but not duration, which was fine in my book.
This is where I tend to be flexible. Rather than forcing a single pattern to meet a single rule set, I'm more interested in whether the broader structure makes sense and whether price behavior respects symmetry. This is why I treat patterns as frameworks, not checklists.
What Happens Next?
What typically comes after the zig-zag down? A bullish reversal! This INTC bullish reversal offered about a 113% retracement (measured A to D), with potential price targets along the way.
How I Personally Think About Targets
When it comes to targets, this is just how I tend to think about it in real time. I'm not rigid, and I'm usually letting price action guide me more than a fixed rule set.
Within the pattern:
Once an AB leg is clearly defined, I'm often already paying attention to the 50%-61.8% retracement area, pattern or not. As price works into that zone and starts to show resistance that helps define point C, I may recognize that an AB=CD structure is forming. From there, I'll measure the AB leg and use that distance as a reference for where the CD leg might extend. I'm generally flexible on timing and more focused on proportion and structure than how long it takes to get there.
Outside of the pattern:
In this specific chart (INTC example), my first area of interest for taking something off would have been the 38.2% retracement from the November 20th lookback—just a small reduction. From there, I'd normally look toward the 50% level, but given the strength of the move and size of the candle at the time, I likely would have allowed price to continue working higher rather than forcing an exit. Price ultimately pushed through the 78.6% retracement, which would keep me patient. The next reference would have been a full retracement back to the A level, and again, because momentum remained strong, I wouldn't have been in a rush. In this case, price extended further, reaching roughly a 113% retracement.
It's less about hitting exact targets (as much as I want to) and more about adjusting as structure and momentum develop.
Closing Thoughts
Patterns like AB=CD are best viewed as tools for organizing market structure rather than standalone answers. For me, the value comes from understanding proportion, symmetry, and context. No two charts are identical, which is why I focus on alignment between structure, momentum, and broader market conditions rather than rigid rules.
This framework is just one of many ways I think about measured moves. Related concepts—such as the 1-2-3-4-5 structure—deserve their own discussion. Future posts will continue to build on these ideas, including measured moves and other market structure frameworks discussed within the PhantomSpot community.
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All content is provided for educational purposes only and does not constitute financial advice.
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