Shares of Roku (ROKU) are in focus on Friday after the stock was downgraded at Wells Fargo, just a day after shares were upgraded at Guggenheim. The ratings changes come after Roku announced a partnership this week with Shopify (SHOP) for TV ad campaigns.

GROWTH POTENTIAL: On Thursday, Guggenheim analyst Michael Morris upgraded Roku to Buy from Neutral with a $395 price target, implying a 22% one-year return. The analyst expects the connected television advertising marketplace will continue to grow at a "rapid" clip and that Roku will be a primary beneficiary, Morris told investors in his research note. Morris also sees value in the company's international expansion and potential for additional targeted marketing partnerships. Roku's expanded advertising tools are underappreciated, the analyst added, also stating that he sees an attractive entry point at current share levels.

Morris estimated that Roku had 5.6 million active accounts outside the U.S. as of June 30, and that number will top 100 million by the end of the decade.

OPPORTUNITY REFLECTED IN ESTIMATES: Meanwhile, Wells Fargo analyst Steven Cahall on Friday downgraded Roku to Equal Weight from Overweight with a price target of $350, down from $488. While Cahall still thinks that Roku has a "long runway" to improve its average revenue per user, or ARPU, he said that this opportunity is now better understood by investors and is reflected in many estimates. The analyst added that Roku's ARPU beat for the second quarter "slowed a lot" relative to the first quarter and he is concerned that the streaming TV competition from players like Amazon (AMZN), Apple (AAPL) and Google (GOOGL) is heating up.

Cahall further noted that Roku fell short with its active account net additions in its most recent quarter, which could suggest that Roku's "valuation is more constrained, especially if net adds aren't accelerating."

WHAT'S NOTABLE: On Tuesday, Roku announced it is launching a new app that will allow Shopify (SHOP) merchants to build, buy and measure TV streaming advertising campaigns. Roku's addition to Shopify's marketing solutions will become the first-ever TV streaming app available in the Shopify App Store, the company said in a statement. Roku's application, which is slated to launch in advance of the holiday season, will enable Shopify merchants of any size to create TV advertising campaigns using precise audiences and measurement throughout their marketing funnel.

"At Shopify, we’re focused on helping our merchants reach more consumers, boost their sales, and build thriving businesses," said Amir Kabbara, Director of Product, Shopify. "By launching the new Roku app in the Shopify App Store, merchants can bring their products directly to TV screens, while allowing consumers to discover exciting new brands right from their living room."

PRICE ACTION: In Friday morning trading, Roku shares are down about 4% to $320.56.