One of Wall Street's major investment banks, Wells Fargo, has made a difficult decision to downgrade Apple, warning that the iPhone 5s is less profitable than previous models and consequently the tech giant can expect lower profit margins and less support from operators in the future.

Though Wells Fargo maintained its price target range of between $536 and $581, the bank cut its rating on the Cupertino-based corporation from "outperform" to "market perform," sending Apple shares down to as much as 1.4pc in early trading on Thursday.

The bank also claimed that it did not expect the introduction of new products, including an internet-connected "iWatch" or a rumored Apple television set, to boost the company particularly.

"There is limited amount of incremental market cap opportunity in the existing product segments Apple plays in (including the television and watch opportunities) without material market share gains," said Wells Fargo analyst Maynard Um. He added that he believes Apple's recent market capitalization gains did not come from increased consumer spending, but it was just the "transfer of dollars" from competitors.

"With less market cap to absorb from its peers and continued pressures on the consumer wallet, we see limited market opportunity absent material share gains," said Um.

In addition, the analyst expressed his concern that smartphone subsidies may become less of a focus for wireless providers. AT&T's CEO said last month that carriers should push toward an ecosystem devoid of subsidies for high-end smartphones. Maynard Um believes that carriers will instead focus on driving device usage to maximize their profitability in the future. He said that this "shifting balance of power" could drag down shares of Apple.

The next iPhone is expected to come with a larger screen than the four-inch iPhone 5s and 5c display and will be introduced in the third quarter of the year.