Apple has been trying to separate its orders to different ODMs to avoid risks. In February 2015, the vendor added Compal Electronics as an iPad mini manufacturer, and Wistron to conduct iPhone touch panel lamination, and has recently outsourced a small portion of its new 4-inch iPhone orders to Wistron, looking to nurture Wistron to become an iPhone assembly house, according to some market watchers.
Notably, Apple is reportedly looking to have Wistron also supply some of its next generation 5.5-inch iPhone Plus orders, alongside Foxconn as the major supplier. Similarly, Pegatron will supply some of its 4.7-inch iPhone orders alongside Foxconn.
Apple is expected to unveil the 4-inch iPhone 5se at a press event on March 15th with orders going live on March 18th.