REUTERS - July 3 - Groupon Chairman Eric Lefkofsky is stepping back from hands-on, operational involvement in Groupon to focus more on his venture capital firm Lightbank. Groupon shares fell almost 11% to close at $9.51 on Monday. The stock was down about 8% earlier in the day and added to losses after Lefkofsky's update. Lefkofsky co-founded Groupon, which was launched in November 2008, with Mason and Brad Keywell. Lefkofsky was also Groupon's first investor, remains a major shareholder and has been a mentor to the young CEO Mason.