The iPhone X is so popular that it just might wind up hurting Apple down the road.
It has been so successful that more and more iPhone users are upgrading early, eating into demand for future generations, according to New Street Research.
The vacuum in sales will be so great that investors should sell the stock, analyst Pierre Ferragu said in a note Monday.
"We expect a material disappointment in 2019," Ferragu said. "The iPhone X has been very successful and well received by consumers. It has been so successful, that we think it has brought forward demand."
IPhone users upgrading early "will drive an 'air pocket,' and the introduction of a lower-price premium OLED phone won't be enough to make up for the shortfall," the analyst added.
Ferragu covered tech stocks for Bernstein for 10 years before joining New Street as head of its global technology infrastructure team. He has covered companies in telecommunications, data networking, cybersecurity and semiconductors.
He now covers such stocks as Apple, Cisco, Tesla and Nokia.
New Street expects iPhone revenues in 2019 will be 10 percent below the Wall Street consensus. For his part, Ferragu believes that Apple's 2019 and 2020 earnings per share will be 9 percent and 6 percent below the average analysts' projections, respectively.
Shares of Apple fell 0.8 percent on Monday. New Research's price target of $165 represents roughly 25 percent downside from Friday's close at $217.58.
"History shows the stock suffers materially when iPhone revenues disappoint," Ferragu said. "This may sound insane, but fits our thesis: iPhone shipments are on a multiple-year decline trend, as refresh cycles elongate, and 2018 was a bump in the trend, as 2016 was."