Reetesh ... actually the number is 20% from the top and the bull market is declated dead. But these things dont exactly apply to commosities as Gold
In 1974-75 dipped 50% from the top and continued with its bull run..
The sequence should make this clear
1970 Gold Was $35 per ounce
1974 Gold was $200 per ounce
1976 Gold was $100 per ounce
1980 Gold was $800 per ounce
Actually the bull continued from $35 To $800, But had a setback of 50% from the top in the middle
50% and 61.8% Retracements happen of a move... Example Gold would be $35 to $200 = Total Move = $165. Now there could be a retracements of 50% or 61.8% of $165
Generally commodities as an asset class display more volatility so Wave overlaps are allowed. However the bull in Stocks is declared Dead when there is a fall of 20% from the top.
These are generally rules.. They need not necessarily apply.