The "unlocked" smartphone market has been growing rapidly across the United States in recent years. However, coupled with the adjustment of Apple’s iPhone Upgrade Program and extended smartphone replacement cycle, as we expected, US unlocked smartphones market posted an annual decline (-3%) in 2018. Motorola maintained the leading position, followed by Apple, BLU, Samsung, LG and Google in US unlocked smartphone market during Q4 2018. Our extensive report contains quarterly unlocked smartphone shipments and market share for the top 18 vendors in the United States from 2013 through Q4 2018. The report also contains US unlocked smartphone forecasts, as well as unlocked iPhone forecasts from 2012 through 2023. This report is a valuable tool for mobile stakeholders who want to size the fast-growing, high-value unlocked smartphone market in US.