It is Gann who liked 50%. He established the 50% rule. Basically...

It is Gann who liked 50%. He established the 50% rule. Basically he said that if the price level of support holds at the 50% level then the upward trend can still be considered strong. Retracement generally happen between 38 and 62% so this one is interesting. If 50% does break there will be a movement down by discouraged Gann technicians. However, Gann then laid out the 75% level as the final last stand and if that breaks there will be no hope left. Anything left and any following uptrend will be slowly played out and have considerably less strength than if the 50% level had never been broken.