He estimates the iPhone subsidy at about $400, compared with $250 to $300 for other smartphones. That means iPhone customers only start to become profitable for carriers about nine months after they buy the device, compared with a five- to six-month timeframe for other smartphones.
As a result, mobile operators' profit margins usually suffer in the months after an iPhone launch, when sales volumes are highest.
"We always say an Apple a day keeps the profits away," Neil Montefiore, chief executive of Starhub, said during the Singapore wireless service provider's August earnings conference call.
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In the United States, carriers have changed their policies to make customers wait longer for a subsidized upgrade and levied new fees, after Verizon Wireless, AT&T and Sprint Nextel Corp suffered dramatic declines in profit margins based on earnings before interest, tax, depreciation and amortization (EBITDA) as a percentage of service revenue in the fourth quarter of 2012, when the iPhone 4S was launched.