People pass by a video sign display with the logo for Roku, a Fox-backed video streaming firm, that held it's IPO at the Nasdaq Marketsite in New York, September 28, 2017.

The worst is over for Roku shareholders this year, according to one Wall Street firm.

Morgan Stanley raised its rating to equal-weight from underweight for Roku shares, citing the company's strong performance in growing its streaming platform.

"Roku benefits from strong secular tailwinds as consumer behavior shifts from viewing TV over traditional distribution (e.g. free-to-air broadcast, cable/satellite/telco) to 'over-the-top' (OTT) internet video consumption, indicating potential upside to account growth and the time spent per account," analyst Benjamin Swinburne said in a note to clients Tuesday. "With shares now down over 25% and core fundamentals consistently coming in ahead of our prior expectations … we view current valuation levels at ~6.5x '19E platform sales as more balanced."