Shares of videoconference developer Radvision (RVSN -35%) nosedive after Cisco Systems (CSCO) -...

|About: Cisco Systems, Inc. (CSCO)|By:, SA News Editor

Shares of videoconference developer Radvision (RVSN -35%) nosedive after Cisco Systems (CSCO) - which RVSN bills for close to 40% of its revenue - agrees to buy its direct competitor Tandberg for almost $3B. "We believe that the company's Cisco-based revenue stream is at risk," Cantor Fitzgerald says, downgrading shares to Sell.