Global smartphone shipments fell -9% YoY to 401 million units in Q4 2017 , while 2017 whole year shipment reached 1.5 billion units, up +1% YoY. Android maintain the leading position but slightly lost ground to iOS during Q4 2017 due to seasonality. All other platforms lost traction. Our extensive report contains global smartphone shipments by operating system by quarter from 2009 to Q4 2017. The report is valuable for mobile stakeholders who want to size the huge market for smartphones and operating system market share.