NEW YORK ( TheStreet) -- Groupon ( GRPN) was a big gainer in premarket trading Thursday after the daily deals site received an upgrade from Piper Jaffray. The analyst firm upgraded Groupon shares to "overweight" from "neutral" and increased its price target to $8 from $5.50, citing improving international business trends and continued strength in North America. Groupon shares rose 4.65% to $5.85 before market open. The Chicago-based firm was also the most active premarket Nasdaq stock on share volume of 247,000. Tesla Motors ( TSLA), however, was a big loser, tumbling 5.68% to $36.35 after reporting mixed fourth-quarter results on Wednesday. Excluding items, Tesla reported a loss of 65 cents a share on $306 million in revenue. Analysts polled by Thomson Reuters were looking for a loss of 53 cents a share on $298.2 million in revenue. The electric car manufacturer was another active premarket Nasdaq stock on share volume of 86,357. Apple ( AAPL) shares dipped 0.45% to $446.85 as hedge fund Greenlight Capital prepares another public attack on the iPhone maker. The hedge fund will host a conference call and Webcast at 2 p.m. EST on Thursday to discuss Apple's capital allocation strategy, which follows hot on the heels of Greenlight Capital's decision to sue the iPhone maker. Shares of ARM Holdings ( ARMH) fell 2.56% to $41.80 while Vodafone ( VOD) slipped 0.65% to $24.53. Zynga ( ZNGA) was off 1.62% to $3.03 in premarket trading. --Written by James Rogers in New York. Follow @jamesjrogers >To submit a news tip, send an email to: firstname.lastname@example.org.