3D Systems (DDD -1.7%) is selling off for the second day in a row. Yesterday, SA's Gray Wolf...

|About: 3D Systems Corp. (DDD)|By:, SA News Editor

3D Systems (DDD -1.7%) is selling off for the second day in a row. Yesterday, SA's Gray Wolf Research offered a lengthy bear case for the 3D printer maker: it argued 3D's organic revenue growth is overstated thanks to acquisitions; that it's losing share after having "significantly underinvested" in R&D relative to Stratasys (SSYS -0.2%) and other rivals; and (citing sources) that 1H results were inflated by channel-stuffing from recently-acquired Z Corp.