Baystreet Staff - Thursday, October 8, 2015 Groupon (GRPN) Reverses Wednesday Jump Groupon Inc (NASDAQ: GRPN) shares tumbled 2.6% to $3.72 after surging 8.8% on Wednesday. Analysts at Cowen initiated coverage on Groupon with an underperform rating. Share volume was 1.1 million, compared to an all-day average of 10 million