Sprint Nextel, one of the four bigwig US wireless providers, witnessed a net loss of a whopping $1.3 billion during fourth quarter, with the key reason behind the ballooning loss figures being the ‘subsidies’ which the carrier offers to its subscribers on the iPhones sold by it.

With the carriers selling the iPhone first needing to buy the handset from Apple and then offer subsides to their customers while reselling the phone, Sprint’s quarterly loss partly resulted from the fact that the price which the company paid for purchasing the phone from Apple was much higher than the cost at which it sold the phone to the customers.

As a result, Sprint became the latest US service provider to be hit by the weight of providing the iPhone. The carrier bought 1.8 million iPhones, spending approximately $630 million – or nearly one-fourth of its total equipment costs - on the purchase. Consequently, the company’s budget swelled by almost 40 percent as compared to the same quarter figures for 2010, before the carrier started offering the iPhone.

However, despite the fact that the weight of the costly iPhone dipped Sprint to a $1.3 billion quarterly loss, the company’s executives have been reiterating that the customers’ payments over time will eventually make the iPhone a money-spinning device for the carrier.

According to Sprint CEO Daniel Hesse, the company is hopeful that “the iPhone will bring significant value to Sprint over the long term, and early results are in line with or better than our business case assumptions.”