He wrote, “In our view, the single most important controversy surrounding Apple today is the iPhone replacement cycle – despite the iPhone installed base growing +9% last year, we now expect units to be down -19% in fiscal 2019, implying a material pushout in upgrade rates.”
Sacconaghi said there is a “myriad of unknowns,” however, including figures for iPhone replacement curves, churn rates, switchers, used iPhone sales and first-time smartphone users, since Apple does not disclose those numbers. “We caution that modeling iPhone’s installed base is as much art as science, with myriad assumptions,” he said.
Apple recently stopped disclosing how many iPhone units it sells each quarter. Instead, in its fiscal Q1 earnings report, Apple started to report an iPhone installed base that includes both new and used iPhones. There are 900 million iPhones in use right now.