Shares of Groupon (GRPN) have gained 12.5% over the past four weeks to close the last trading session at $12.87, but there could still be a solid upside left in the stock if short-term price targets of Wall Street analysts are any indication. Going by the price targets, the mean estimate of $16.88 indicates a potential upside of 31.2%.The mean estimate comprises four short-term price targets with a standard deviation of $7.94. While the lowest estimate of $7.50 indicates a 41.7% decline from the current pri ...