T-Mobile is the only major U.S. carrier that is not selling the iPhone 5 right now, but that may change next year, according to at least one analyst.

The carrier could "announce official iPhone distribution in early 2013," Nick Delfas, a Morgan Stanley analyst, told CNET.

Delfas added that the move would put the iPhone 5 on T-Mobile in the hands of about one million to two million new customers in the first quarter alone.

Earlier this month, T-Mobile began selling iPhone 5-friendly nanoSIM cards as a way to unofficially bring iPhones to its network.

However, the costly arrangement requires an unlocked iPhone 5 from Apple or one of three official carriers: AT&T, Verizon or Sprint.

T-Mobile's buildup to the iPhone 5

While T-Mobile employees were reportedly told to sell against the iPhone 5, the fourth-place U.S. carrier has at the same time worked to improve its iPhone-compatible 4G network.

A $4 billion invest recently lead to Las Vegas being the first city with the iPhone-friendly HSPA+ 1900 MHz frequency activated. More metropolitan areas are expected to see the same LTE treatment in 2013.

In addition to its iPhone 5-compatible speed boost, T-Mobile announced its merger with MetroPCS in exchange for a $1.5 billion shareholder payout.

Combined with the no-contract carrier, the T-Mobile customer base is 42.5 million.

That's still just 11.7 percent of the U.S. wireless market, but an attractive enough chunk of customers for Apple to seriously consider adding to it already impressive iPhone 5 sales.

Via CNET, Business Week