Apple has 42% of the smartphone market in the U.S. A larger iphone with 5.5 inch screen could generate a meaningful upgrade cycle, say analysts, increasing Apple's market share by 11%. The larger device is especially important in emerging markets where the iphone serves as the main computing device. Samsung currently dominates the larger screen market with 34%, followed by Lenovo. The shift to larger screens is significant- market research firm Canalys estimates that 40% of global smartphone shipments were larger than 5 inches in the 2nd quarter of 2014, up from 21% the prior year quarter. This is the one area in which Samsung holds an advantage.