Apple has started scaling back on chip orders for its latest iPhone, according to sources at IC design houses.

Orders for chips for the production of iPhone 6 devices will reduce to 44-46 million units in the first quarter of 2015 from more than 50 million units in fourth-quarter 2014, the sources estimated.

In addition, analog IC firms in the supply chain for Apple's iPhone 6 disclosed that their unfilled orders-to-shipments ratio has slid to 1.1 from 1.3-1.4.

Meanwhile, sources at downstream manufacturers also indicated that the visibility of orders for the iPhone 6 has reduced at a gradual pace. Shipments for Apple's latest iPhone devices might have already reached peak levels, the sources suggested.