Editing Gann angles (section)

{{more citations needed|date=February 2018}}

The '''Gann angles''' are named after [[W. D. Gann]], a 20th-century [[Market (economics)|market]] theorist. Gann described the use of the angles in the [[stock market]] in ''The Basis of My Forecasting Method'', a 33-page course written in 1935. The legitimacy of Gann's techniques has been seriously questioned. Calculating a ''Gann angle'' is equivalent to finding the [[derivative]] of a particular line on a chart in a simple way.<ref>
{{cite book
 | title= Technical Analysis from A to Z: Covers Every Trading Tool from the Absolute Breadth Index to the Zig Zag
 | first= Steven B.
 | last= Achelis
 | publisher= McGraw-Hill Professional
 | year= 2000
 | ISBN= 0-07-136348-3
 | url-access= registration
 | url= https://archive.org/details/technicalanalysi00ache
 }}
</ref>

A Gann angle is a straight line on a price chart, giving a fixed relation between time and price. For Gann the most important angle was the line which represented one unit of price for one unit of time, called the 1x1 or the 45° angle.
The value of a commodity or stock following this angle will for example increase by one point per day. Other important angles were the 2x1 (moving up two points per day), the 3x1, the 4x1, the 8x1, and the 16x1.
In addition to these value increases, the corresponding angles for value decrease are just as important.
When several of these angles are drawn in a group, they are often called a '''Gann fan''', which is usually drawn from a price bottom or a price top.

As with other forms of [[technical analysis]] of stock price movements, the Gann angle model contradicts the weakest form of the [[efficient-market hypothesis]] which states that past price movements cannot be used to forecast future price movements.