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.

Shares of Roku spiked Friday after short-seller Citron Research said it is reversing its negative view on the maker of streaming players, given a major shift away from the traditional cable television subscription model.

"The move to cutting the cord and [over-the-top] advertising is real and it is a megatrend that Citron not only does not want to be short, but at this valuation I want to be long," the research firm, headed by Andrew Left, said in a report Friday.

Roku shares climbed more than 7 percent, closing at $38.54 a share. The stock is down roughly 25 percent for the year so far.

After the company went public in late November, the stock soared above $50 and Citron said it tweeted the stock would fall back to $28.

"BUT NOW EVERYTHING HAS CHANGED, AND IT IS TIME TO REEVALUATE," the report said, in red capital letters.