Trends/Fibonacci and harmonic patterns

ABCD pattern

A four-point zigzag where the last leg is about the same size as the first, with a pullback in the middle.

Fibonacci and harmonic patternsBest on 3M, 6M, 1YAlso called AB=CD

Illustration of the ABCD pattern shape. It is a sketch, not real price data.

What it shows

The ABCD pattern has four points. A to B is the first leg, B to C is a pullback of 61.8% to 78.6% of AB, and C to D is the last leg, equal to AB or 127.2% to 161.8% of BC.

It is the simplest harmonic pattern and the base for more complex ones.

How we find it

The same code that draws it on your chart follows these steps, with the same result every time.

Find four alternating swing points A, B, C, D.
BC must retrace 61.8% to 78.6% of AB.
CD must equal AB (±10%) or be 127.2% to 161.8% of BC.
Mark complete at D.

Starting values: BC retracement 61.8% to 78.6% of AB; CD equal to AB (±10%) or 127.2% to 161.8% of BC. These are proposed and will be tuned on real price data before launch.

How to read it

Dots are the four points.
The first and last legs are about the same size.
The dashed lines show the AC and BD links.

Status labels you may see

Label	What it means
Pattern forming	A, B, C found, D not reached.
Pattern complete	D matches the rule.
Invalidated	Price closed beyond B.

What cancels it

A close beyond point B.

What traders check next

Whether the legs are equal in size and in time.
What happened at D.
Whether other levels agree with D.

Limits

Equal legs are common by chance.
Tolerance lets many shapes qualify.
Rarely tested in research.

Try it in forecastviz

Open any ticker and choose Fibonacci and harmonic patterns → ABCD pattern in the left menu.
Switch between 3M, 6M, 1Y to see how the picture changes.
Compare with Measured move up and Measured move down on the same chart.

Open on a ticker

Questions

How is it different from a measured move?

An ABCD adds a rule for the pullback.

Is it harmonic?

Yes. It is the base of the harmonic family.