Par Pharmaceutical Companies, Inc. (PRX) received a brokerage firm upgrade today, which is helping it to gain during a rather muted morning session. In addition, PRX has been enjoying rising earnings estimates that have pushed the 2009 and 2010 Zacks Consensus Estimates higher in just the past 7 days. The company made the Zacks #1 Rank Top [...] (PRX) Top Performer for Thurs: Par Pharmaceutical Companies