Speculation about Apple cutting back its orders for iPhone devices and related components has been fueled by revelations by more Taiwan-based suppliers that their orders from the US client for its smartphones have been reduced or delayed, according to industry sources.

Concerns about Apple reducing orders have grown after Apple's main chip manfacturing parterner, Taiwan Semiconductor Manufacturing Company (TSMC), released its lower-than-expected guidance for the second quarter of 2018 recently.

TSMC expects its second-quarter revenues to reach US$7.8-7.9 billion, down 6.6%-7.8% from a quarter earlier, and the figures are about US$1 billion less than analysts had projected.

TSMC also said its gross margin for the second quarter will stand at 47%-49% compared to 50.3% seen in the first quarter.

Sources from Taiwan's foundry industry indicated that TSMC's capacity utilization rates of its 10/16 nm processes have been undermined significantly in the second quarter due to reduced orders from the iPhone supply chain.

The sources also noted that some touch panel makers, which had been operating at a three-shift schedule to meet orders, have now cut back the workload for the night shift, due to product transition at Apple.

Additionally, the visibility of Apple's orders for the third quarter of 2018 is still not clear, and therefore most suppliers are not expected to see a rebound of Apple's orders until the middle of the third quarter, said sources.

Meanwhile, component orders for new iPad and MacBook products are also likely to be delayed, the sources added.