T-Mobile shares rose over 4 percent in premarket trading Thursday, a day after the telecommunications company announced quarterly earnings that far surpassed expectations.
Later in the morning, T-Mobile shares dipped 0.4 percent lower from Wednesday's close.
Second-quarter revenue of $10.21 billion thrashed Reuters estimates of $9.81 billion. Net adds, which are an important measure of the number of customers added during the quarter, hit 1.33 million, exceeding the 807,000 expected by Street Account.
The S&P 500 was up about 2 points in premarket trading.
T-Mobile has been embroiled in intense competition with other mobile carriers as consumers increasingly demand unlimited data plans ahead of the release of 5G phone chips.
"In Q2, we delivered our highest absolute service revenue ever with 8% year-over-year growth and 10% in total revenues where we expect to lead the industry for the 16th time in the last 17 quarters," T-Mobile CEO John Legere said during Wednesday's conference call.
"If you're looking for the big news from Q2, you could simply say that T-Mobile's business continues to perform at peak levels."
Legere credited the impressive quarter's numbers to investments in the network as well as "good, old-fashioned focus" from engineers.
As of Wednesday's close, T-Mobile stock had risen nearly 8 percent this year.