Citi Downgrades Stratasys To Neutral, 3D Systems To Sell By: Benzinga via Benzinga April 15, 2016 at 07:32 AM EDT Shares of 3D Systems Corporation (NYSE: DDD) have surged 110 percent YTD, while Stratasys, Ltd. (NASDAQ: SSYS) shares have climbed 22 ... Read More >> Related Stocks: 3D Systems Corp Stratasys Ltd