T-Mobile claims it surpassed Sprint's subscriber base as of the fourth quarter. Photo Illustration/IBTimes Source Images: Reuters

T-Mobile hit a lot of milestones in 2014, including surpassing rival Sprint in subscriber base, if CEO John Legere is to be believed. The mercurial head of T-Mobile claims that Sprint’s reported figures don’t tell the whole story about its market share.

T-Mobile reported a total of 52.9 million subscribers at the end of its third quarter. With the addition of 2.1 million subscribers in its fourth quarter, the carrier now claims 55 million customers, almost tying with Sprint, which reported 55.9 million subscribers at the end of its fiscal third quarter. But Legere said that Sprint, by counting inactive, third-party carriers that ride on its network (known as mobile virtual network operators, MVNOs), has been skirting the unwritten rules of wireless carriers to make it appear as if it has more customers than it does.

Legere made the accusation during T-Mobile’s fourth-quarter earnings call Thursday.

He went on to say that within Sprint’s filings with the Securities and Exchange Commission is evidence of 1.7 million inactive accounts that have yet to be terminated by the carrier. Sprint has used these accounts to maintain its subscriber figures, according to Legere. Otherwise, Sprint’s figures would look much different.

Sprint did see subscriber growth between its fiscal second quarter, when it reported 53.9 subscribers, and its fiscal third quarter. But Legere said the network’s growth has remained flat between 2013 and 2015. Sprint said its longstanding policy has been to maintain accounts unless an MVNO notifies it of extended inactivity, according to CNET.

Doubling down on his promise to surpass his closest rival, Legere said that T-Mobile should have a clear lead ahead of Sprint within the next two quarters.

T-Mobile reported a quarterly profit of $101 million, or 12 cents a share, for the fourth quarter, which greatly exceeded analysts’ expectations. The network saw an almost 20 percent increase in revenue to $8.15 billion. Analysts polled by Thomson Reuters predicted T-Mobile’s earnings would yield 5 cents a share and revenue of $7.89 billion.