Perhaps the biggest threat to Roku comes by way of Walmart's recent deal to buy TV manufacturer Vizio, and its Smartcast OS, according to one analyst.

Just over a month after Walmart closed a $2.3 billion deal to acquire Vizio to help further its ambitions in the connected TV ...

Roku competes with Alphabet Inc. (NASDAQ: GOOGL), Google TV OS, Walmart Inc. (NYSE: WMT), VIZIO, and SmartCast OS. While Roku currently works with The Trade Desk, they have also launched their own ...

Roku (NASDAQ: ROKU) stock has gone from boom ... With the acquisition also comes Vizio's SmartCast operating system, which has 19 million active accounts.