India and Vietnam were the most favoured for the manufacture of components used in Apple iPhones, the Nikkei Asian Review reported citing anonymous sources.
The evaluation has been driven by the ongoing US-China trade war but indications are that the shift might take place even if a deal was hammered out between Beijing and Washington.
One executive was quoted as saying: "A lower birthrate, higher labour costs and the risk of overly centralising its production in one country. These adverse factors are not going anywhere.
US President Donald Trump and his Chinese counterpart, Xi Jinping, are expected to meet at the G20 leaders' summit which is due to be held at the end of the month, but there are few indications that they will come to an agreement on ending the existing trade tensions.
Trump first imposed a 30% tariff on solar panel imports on 7 February last year, followed by a 25% tariff on all steel imports. to which Beijing retaliated on 2 April with tariffs on fruit, wine, seamless steel pipes, pork and recycled aluminium.
Since then, the tit-for-tat tariffs have been ratcheted up and as of today US$250 billion of Chinese goods have been targeted by Washington while US$110 billion of goods have been slugged with tariffs by Beijing.
About five million Chinese workers owe their jobs to Apple's operations in China, including some 1.8 million software and App developers. Apple has 10,000 workers in China.
Among the companies that have been asked to calculate the costs of moving out are iPhone suppliers Foxconn, Pegatron, and Wistron, MacBook manufacturer Quanta Computer, iPad producer Compal Electronics, and AirPod makers Inventec, Luxshare-ICT and Goertek.
It has been estimated that it would take at least a year and a half before production can start in any new location.