A report by Danish analyst firm Strand Consult has claimed that mobile operators' profits are being hit by the decision to carry Apple's iPhone.
Apple has traditionally signed up with one mobile operator in each country, such as AT&T in the US and O2 in the UK.
AT&T's profits were down slightly during its most recent quarter, but it has increased its market share using the iPhone and wants to keep the exclusive deal.
"We have not found one operator which has created shareholder value with the iPhone," Strand Consult told Reuters.
"According to the research we have conducted on the operators, not one of these has increased their market share, revenue or earnings as a result of introducing the iPhone. On the contrary, some operators have sent out profit warnings because of the iPhone."
The firm cited examples such as SingTel, south east Asia's largest phone firm, which had seen operating profit margin drop by three to four percentage points after introducing the iPhone.
TeliaSonera, which sells the iPhone in all Nordic countries, had seen no boost in market share, and its average revenue per user had fallen in Denmark and Sweden by more than the competitions'.
The analysts noted that other manufacturers are catching up with Apple's technical and usability advantages, and are winning over users in some cases.
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