By Marina Lopes
WASHINGTON (Reuters) - T-Mobile US
The declaration came a day after T-Mobile said it surpassed Sprint as the No. 1 wireless provider for prepaid customers, with 15.64 million users, compared with Sprint's 15.19 million.
The figures put T-Mobile, which calls itself the "uncarrier," well ahead of rivals AT&T
"I predict the #uncarrier will overtake @Sprint in total customers by the end of the year! There, I said it!," tweeted Legere.
A spokeswoman for Sprint declined comment.
While T-Mobile has been adding record numbers of subscribers through promotions and campaigns, Sprint customers have been leaving in droves because of service problems arising from carrier's network overhaul.
Earlier this week, Sprint's parent company, SoftBank Corp <9984.T>, walked away from its offer to buy T-Mobile and replaced Sprint CEO Dan Hesse with Miami businessman Marcelo Claure.
Legere, known for his outspoken style, did not waste time in engaging with his new competitor, and tweeted at Claure on Thursday "Sorry @marceloclaure, you're already behind!."
While T-Mobile's aggressive strategy has helped the company turn around, its parent company, Deutsche Telekom <9984.T>, has been concerned that its lack of low-frequency spectrum and fixed-line infrastructure is hampering its ability to compete.
The company will have to spend an estimated $5 billion to $10 billion in the upcoming auction of radio frequency waves, according to one analyst, the first public auction of valuable low-frequency airwaves in nearly a decade.
T-Mobile shares were down 4.3 percent and Sprint shares were down 0.8 percent after falling nearly 20 percent on Wednesday.
(Reporting by Marina Lopes; Editing by David Gregorio)