Stephens analyst Kyle Evans downgraded the stock to equal weight from overweight, writing that the shares now look riskier following a big rally. Roku shares are up more than 200% so far this year. "The simple math on current Roku estimates is that the lowest sell-side ratings/targets have the highest estimates, and most hold/sell analysts now have 2Q19 estimates above consensus and 2019 estimates above company guidance," Evans wrote. "While this setup isn't rare, we do believe it creates real near-term risk for Roku given its current valuation and historical volatility."