While Apple's iPhones, iPads and Macs remain gold standards, signs the company is losing some of its edge in the smartphone market suggest its clout with business partners could wane.

Recent comments from executives at phone carriers and component suppliers show they see room for at least some shift in the balance of power.

In particular, a move by No. 4 US mobile service provider T-Mobile USA to stop subsidizing smartphones around the time it starts selling the iPhone in three months time may put pressure on Apple, especially if other carriers follow the example.