"He's been an extremely good buyer of the stock," Mahaney said. "If he were to sell, I wouldn't change our opinion, but we'd note it as a clear negative on the stock. He knows what he's doing with Netflix so far."
Icahn, the billionaire activist investor and chairman of Icahn Enterprises, holds 10 percent of Netflix's outstanding shares
(Read more: Internet's top 'utility' stocks: Mark Mahaney)