Bank of America continued to be positive on Roku (NASDAQ:ROKU) after its shares reacted negatively on Wednesday to the report of Trade Desk's (NASDAQ:TTD) new TV operating system, Ventura.

The research firm noted Roku's shares were down about 7% on the threat of a new competing connected TV OS but pointed out that the company has been successfully competing in a crowded TV OS space all this while.

BofA thinks it will likely take several years for Trade Desk to establish its relationships with TV OEMs for it to materialize into some form of competition against Roku. They added that Roku's OS continues to lead the North American market, and TV OEMs see real value in using its OS.

"In many ways, Roku outsources a lot of the TV OEMs’ R&D costs while at the same time helping them with demand generation. This has helped Roku’s TV OEM partners take market share over time," BofA said in a November 21 note.

"We reiterate our Buy rating on Roku on its large scale, new partnerships with media networks and DSPs, which we believe improves access to advertisers and helps fill rate, and longer-term international expansion opportunity," they added.

ROKU has an unchanged PT of $90, implying an upside of 31%.