By StrategyAnalyticsAccording to the latest research from our Handset Country Share Tracker (CST) service, Apple’s iPhone 5 overtook Samsung’s Galaxy S3 to become the world’s best-selling smartphone model for the first time ever in the fourth quarter of 2012. A rich touchscreen, extensive distribution and generous operator subsidies have propelled the iPhone 5 to the top spot. Apple’s iPhone 5 smartphone model shipped an estimated 27.4 million units worldwide during the fourth quarter of 2012. The iPhone 5 captured an impressive 13 percent share of all smartphones shipped globally and it has become the world’s best-selling smartphone model for the first time ever. A rich touchscreen design, extensive distribution across dozens of countries, and generous operator subsidies have been among the main causes of the iPhone 5’s success. In addition to the iPhone 5, Apple shipped an estimated 17.4 million iPhone 4S units for 8 percent smartphone share globally in Q4 2012. Apple’s iPhone 5 and iPhone 4S are currently the world’s two most popular smartphone models.