Smartphone shipments in the United States were down -14% annually in Q4 2018, as consumers continue to upgrade less frequently. Apple was number one in hardware, while Android captured top spot in software. T Mobile delivered a great performance; its uncarrier strategy is proving highly successful. This report tracks smartphone shipments, vendor marketshare, and OS marketshare for 20 major brands and 4 major platforms in the United States across 4 top operators and the total market on a quarterly basis from Q1 2011 to Q4 2018. Operators covered include Verizon Wireless, AT&T, Sprint and T Mobile.