lowtrade

[trader guy]

The volume pattern you describe is not always required.

Volume: In an ideal pattern, volume levels will track the shape of the rounding bottom: high at the beginning of the decline, low at the end of the decline and rising during the advance. Volume levels are not too important on the decline, but there should be an increase in volume on the advance and preferably on the breakout.
http://stockcharts.com/help/doku.php?id=chart_school:chart_analysis:chart_patterns:rounding_bottom_reve

In the case of ATRN the stock dropped on very little volume and bottomed on huge volume because that is where the conversion price was reached and shares converted and sold. However, there is no way to put a value on the breakout volume in the case of the rounded bottom breakout (the pennant breakout may be occuring now...the rounded bottom breakout has yet to occure) because there is no way to know what the true float is until it is reported.