Netflix hit an all-time high of $671.10 on Wednesday, but Wall Street's biggest bear on the stock, Wedbush Securities' Michael Pachter, told the "Fast Money" traders he thinks the stock is widely overvalued—and he won't back down.
"I'm not going to cave on a price target until I see evidence that cash flow is growing. These guys have visibility to $40-$50 a share in earnings, and I don't see that coming in the next five years," Pachter said.
While Netflix has soared more than 97 percent in the past six months, Pachter stressed that the streaming service hasn't outpaced analysts' expectations on actual earnings estimates, only on subscriber growth.
"I'm wrong on the share price," said Pachter, "and I'm going to be wrong as long as investors suspend disbelief and are willing to pay for subscriber growth only."
According to Netflix's recent earnings report, the service had surpassed 40 million members in the U.S. and 20 million abroad as of April 15. That's a 29 percent increase from the same period in 2014.
"I suppose that if you're willing to pay for subscribers and just trust that someday when Netflix decides to charge $20 or $30 a month, nobody will quit and no competitors will enter, then it probably is worth $670 a share; I just don't think that is going to happen," said Pachter, who has an underperform rating and a $270 price target on the stock, by far the lowest on the Street.
Netflix has been touting accelerated growth into 200 countries by the end of 2016. It's currently available in more than 50 countries.