iPhone 7 supply remains constrained, Apple viewed as unlikely to catch up to demand by end of year

Analyst Gene Munster of Piper Jaffray polled 134 U.S. Apple stores and found that just 47 percent of iPhone 7 models were in stock. While the 4.7-inch iPhone 7 has 91 percent availability, just 3 percent of 5.5-inch iPhone 7 Plus models were available in stores.

Supplies are even more constrained in China, where iPhone availability is just 16 percent — a slight improvement from 12 percent a month ago. There, Piper Jaffray has been tracking online stock from carrier China Unicom.

In contrast, by this point a year ago, the iPhone 6s had reached 100 percent availability at Apple's retail stores. To Munster, this suggests demand for the iPhone 7 series is outpacing last year's iPhone 6s.

As a result, Munster believes it is now unlikely that Apple will reach supply-demand equilibrium by the end of the December quarter, which includes the lucrative holiday shopping season.

AppleInsider reported in late September that initial iPhone 7 availability was restricted by an international freight logjam. Munster's findings correspond with that to some degree — while overall iPhone 7 model availability stayed at 35 percent from late September to mid October, it jumped to 46 percent by the end of October.

Munster has forecast iPhone unit growth of 3 percent year over year for the December quarter. He also expects that tight iPhone 7 supply at Apple stores is a slight positive sign for the following March 2017 quarter.

Apple has been mum on iPhone 7 sales, opting this year to not reveal opening weekend sales, citing the fact that demand at launch always outstrips available supply. The conclusion of the December quarter will represent the first full quarter of iPhone 7 series sales, giving investors and industry watchers their first indication of how the new models are performing.