Why on Earth Is Roku’s Stock So Ridiculously Expensive?

You’ve just witnessed the semi-annual Roku Inc. sell-off. It’s the time of year when investors come to the abrupt realization that they’ve probably paid too much to own shares of the high-flying streaming-TV company, as if valuing anything at 300 times Ebitda were ever rational.

Here’s how it usually goes down: An equity analyst downgrades Roku, sending the stock into a tailspin, which leaves onlookers wondering what terribly bad thing occurred at the company — or what a Roku even is. This time, that analyst was Benjamin Swinburne of Morgan Stanley. He cut his rating to the equivalent of a “sell,” and oh, did the market listen: Roku plunged 15% on Monday for one of the Nasdaq’s worst post-Thanksgiving showings.