I don't follow PLX but I just decided to look up the dates of these sales, and to check how it matches with the chart. I don't see where Frost was selling PLX since Nov 2010... 9/11/2009 is the last sale I see. I do see he added 71K shares of PBTH since May6. http://www.secform4.com/insider-trading/1006281.htm images.investorshub.advfn.com/images/uploads/2011/7/22/mkbxdScreenHunter_1100.jpg http://www.secform4.com/insider-trading/1268659.htm images.investorshub.advfn.com/images/uploads/2011/7/22/ksflqScreenHunter_1101.jpg