Apple ( AAPL ) has already signaled that iPhone unit sales will decline on a year-over-year basis for the first time ever in the March quarter. But investment bank Canaccord Genuity believes they could decline for three straight quarters before getting a boost from the iPhone 7 launch this fall. “Based on our survey work and analysis, we believe Apple is maintaining strong share of the premium-tier smartphone market,” Canaccord analyst Michael Walkley said in a report Wednesday. “However, given the similar form factor for the iPhone 6S and softer smartphone global demand trends, we anticipate down year-over-year iPhone sales for the remainder of fiscal 2016.” Apple’s fiscal 2016 ends on Sept. 24. The Cupertino, Calif.-based company is scheduled to report fiscal-second-quarter results on April 25 after the market close. Walkley expects iPhone users to delay upgrading their handsets until the iPhone 7 is released, likely in September. “While initial sales of the iPhone SE should help offset a portion of slowing overall iPhone sales, we anticipate down year-over-year iPhone sales for the next three reported quarters,” he said. “Longer-term, we believe the current iPhone 6 and iPhone 6S products have enabled Apple to materially increase its share and installed base of the premium-tier smartphone market with Android users switching to the iPhone.” Walkley reiterated his buy rating on Apple stock with a price target of 146. Apple was flat near 112 in midday trading on the stock market today . In January, Apple said it sold 74.78 million iPhones in its fiscal Q1 ended Dec. 26, up 0.4% from the same quarter a year earlier. However, in February, research firm Gartner said Apple iPhone sales to end users fell for the first time on a year-over-year basis in the December quarter. Gartner estimates that Apple’s calendar-fourth-quarter iPhone sales declined 4.4% year over year to 71.5 million units. Apple counts iPhones sold into the sales channel, not those sold through to end customers, in its financial reports. RELATED: Teens Still Crave iPhones, But Not So Much Into iPads, Apple Watch Apple Price Target Cut On Lengthening iPhone Replacement Times .