UPDATE: Yelp Upgraded by Citigroup, U.S. Penetration Only at 3% By: Benzinga via Benzinga April 16, 2014 at 08:42 AM EDT Shares of Yelp (NYSE: YELP) are up three percent to $64.90 in Wednesday's pre-market trading after being upgraded by Citigroup from ... Read More >> Related Stocks: Yelp Inc