Facebook (FB) shares are surging today with the overall market after two analysts released upbeat notes about the company. JP Morgan analyst Doug Anmuth expects the social network's ad revenue to accelerate at least through the current quarter, and he increased his estimates for the company's 2013 and 2014 ad revenue by 6%-7%. Companies have been pleased with the results they have obtained from their ads on Facebook, wrote the analyst, adding that Wal-Mart (WMT) appears to have significantly increased its spending on the platform. Anumth increased his estimates for Facebook and raised his price target on the shares to $35 from $29 while maintaining an Overweight rating on the name. Also upbeat on the stock was William Blair analyst Ralph Schackart. Facebook Exchange - a new ad product which enables advertisers to target users based on their browsing histories - should be beneficial to the company's business over the long term, the analyst wrote. Moreover, after meeting with ad agencies and marketers, Schackart believes that Facebook ad prices could potentially jump by 300%. The analyst maintained an Outperform rating on the shares. In early trading, Facebook rose $1.05, or 3.95%, to $27.67.