Amit Daryanani with RBC Capital Markets said in a note to investors on Thursday that with about 33 million subscribers on T-Mobile, Apple could sell about 4.8 million iPhones in the first year.
He noted that Sprint, which is the third-largest carrier in America, sold 6.3 million iPhones in the first year of availability. That represented about 20 percent of the total number of postpaid subscribers at Sprint.
Of T-Mobile's 33 million subscribers, about 70 percent of those are postpaid. That means there are about 24 million postpaid subscribers that Apple could target.
Assuming the same 20 percent of those buy an iPhone that did so on Sprint, that puts Apple in line to sell 4.8 million units in the first year. As such, Daryanani had projected that the addition of T-Mobile USA as an official carrier partner will net Apple between 4 million and 5 million more iPhone sales.
He assumes those iPhones sold to T-Mobile customers would have an average selling price of about $600 and gross margins around 50 percent. that would add more than 60 cents to RBC's projected $50 earning-per-share estimate for Apple's fiscal year 2013.
T-Mobile's parent company, Deutsche Telekom, announced earlier Thursday that it has reached an agreement with Apple to begin selling the company's products in America next year. Though specific products were not mentioned, the company's CEO later confirmed that its U.S. branch will indeed begin selling the iPhone next year with a "dramatically different" experience for customers.
According to GigaOm, that experience will entail T-Mobile's unsubsidized "Value Plans," which will feature cheaper rates for voice and data, but will require customers to pay a larger upfront cost to buy a new phone. T-Mobile is transitioning after 80 percent of its customers last quarter opted for Value Plans.
While an unsubsidized, unlocked iPhone starts at $649 through other carriers, T-Mobile USA CEO John Legere implied that his company will lessen the burden on customers by offering a monthly finance plan, charging a flat sum up front and then a monthly fee thereafter to pay off the device in installments.
Beyond the iPhone, Daryanani believes iPad sales through T-Mobile would offer even more upside potential, particularly with the entry-level iPad mini. If T-Mobile were to add an additional 2 million in incremental unit sales, i would equate to an additional 25 cents to Apple's projected earnings per share .
RBC Capital Markets has maintained its "outperform" rating for AAPL stock with a price target of $750.