T-Mobile's "Uncarrier" campaign continues to pay dividends in the form of new customers.

The Bellevue, Washington-based wireless carrier said Thursday that it added a net 2.1 million subscribers in the second quarter, boosting its subscriber base to 58.9 million as of the end of that three-month period.
The numbers represent the latest surge in the neck-and-neck race between T-Mobile and Sprint, the smaller of the big four US carriers, behind Verizon Wireless and AT&T. The wireless market is in a state of flux as all the carriers, and especially the smaller two, tinker with coverage plans, customer promotions and network upgrades in a quest for every edge they can get.
At the end of the first quarter, T-Mobile was the nation's fourth-largest wireless carrier, with 56.8 million customers, roughly 300,000 behind Sprint's 57.1 million-strong customer base. While T-Mobile has ridden a sustained wave of momentum over the past two years, Sprint in the last several months has gotten more aggressive in adding customers.
T-Mobile CEO John Legere had promised to eclipse Sprint by the end of last year, but the Overland Park, Kansas-based carrier has hung on to its lead. T-Mobile has argued that Sprint's accounting method tallies a number of customers from resale partners that have been inactive for at least six months and that those figures shouldn't count toward its total. Sprint has defended the accounting practice, noting that its policy is not to remove a customer from its records until a resale partner notifies it.
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The gain of 2.1 million customers represents 41 percent growth over a year ago, and above the 1.8 million customers T-Mobile added in the first quarter. The total includes the addition of 1 million new T-Mobile-branded customers who pay at the end of the month -- a lucrative type of customer known as postpaid. Out of the 1 million, 760,000 were phone customers.
T-Mobile also added 178,000 branded prepaid customers, largely through its MetroPCS arm.
The customer turnover rate for its branded postpaid base was 1.32 percent, down from a year ago, but a slight tick up from the first quarter. The customer turnover rate for its prepaid business also rose from a year ago and the first quarter.
More clarity on which carrier is the legitimate No. 3 will come in the next few weeks, once T-Mobile and Sprint both report their full quarterly results. T-Mobile said it will report full results on July 30.