Strategy Analytics tracked global smartphone shipments (sell in) remained flat annually in May 2021 because of the weak performance on Asia Pacific region due to COVID-19 second wave outbreak and the mixed performance of China market. Sales volume improved +13% YoY. However, both shipment and sales registered a sequential decline from April 2021. Samsung maintained the top position, followed by Xiaomi, Apple, OPPO and vivo etc. This report tracks global smartphone monthly shipments (sell in), sales (sell through) and inventory changes by 32 of the world's largest vendors from January 2016 to May 2021. The report is a valuable tool for OEMs, component makers, software developers, operators and other stakeholders to track key OEMs inventory level and support their planning activities.