Makes me wonder, how did we gain over 7 % thru all

Makes me wonder, how did we gain over 7 % thru all of that short volume? I assume some were covering at the end of the day, not wanting to be short ove the weekend.  Usually,there seems to be more buying in the morning and more selling in the afternoon.  But this was a nice close and decent volume for the day.  Someone who knows more than me, go ahead and chime in.  My best to you,  Jim