VirnetX Downgraded to Sell

2:51 PM ET Mon, 8 Oct 2012

Green Dot, a prepaid debit card company, is in the red right now and could be hurting further if American Express gets into the business. And Craig-Hallum downgraded VirnetX to sell, noting "current valuation implies values for patents that are much higher than any comparable valuation we've seen applied to patents elsewhere," with CNBC's Herb Greenberg.