Shares of Roku Inc. are up 4.4% in Tuesday trading after Oppenheimer analyst Jason Helfstein upgraded the stock to outperform from perform. "We believe The Roku Channel is 0.63% of domestic time-spent on Roku's platform or the 12th most-watched app by viewing hours, which represents a 9 million hour monthly run-rate only nine months post-launch," he wrote of a collection of free, ad-supported movies that are available on Roku's platform. "The rapid adoption of The Roku Channel gives us incremental confidence in the channel's ability to garner viewership on other platforms, such as Samsung, allowing Roku to monetize a broader portion of the OTT ecosystem than we had previously assumed was possible." Helfstein has a $50 price target on the stock, which is up more than 40% over the past three months, compared with a 4.6% rise for the S&P 500